chore: Update discovery artifacts (#1438)

## Deleted keys were detected in the following stable discovery artifacts:
youtube v3 https://github.com/googleapis/google-api-python-client/commit/ec21dff96d9538ad6c7f9b318eca88178533aa95

## Deleted keys were detected in the following pre-stable discovery artifacts:
firebasehosting v1beta1 https://github.com/googleapis/google-api-python-client/commit/c83ac386b65f82e7ba29851d56b496b09a29cf98

## Discovery Artifact Change Summary:
feat(analyticsadmin): update the api https://github.com/googleapis/google-api-python-client/commit/96675a8d9158ec13353fe241f858201fc51b784d
feat(composer): update the api https://github.com/googleapis/google-api-python-client/commit/add2fbdc3afb6696537eb087bc1d79df9194a37a
feat(container): update the api https://github.com/googleapis/google-api-python-client/commit/f8fae98db6d1943411b1a6c0f5a65dea336569f6
feat(content): update the api https://github.com/googleapis/google-api-python-client/commit/0814e009a4a11800db5b4afd7b6260e504c98047
feat(datacatalog): update the api https://github.com/googleapis/google-api-python-client/commit/99706059e58bb3d616253a1af2cd162b5a0b0279
feat(dataflow): update the api https://github.com/googleapis/google-api-python-client/commit/d5f09ef30392532bcfdd82901148bdd3ac6eec01
feat(docs): update the api https://github.com/googleapis/google-api-python-client/commit/dc66f4cafba86baff6149b2f6e59ae1888006911
feat(file): update the api https://github.com/googleapis/google-api-python-client/commit/523fc5c900f53489d56400deb650f6586c9681a0
feat(firebasehosting): update the api https://github.com/googleapis/google-api-python-client/commit/c83ac386b65f82e7ba29851d56b496b09a29cf98
feat(healthcare): update the api https://github.com/googleapis/google-api-python-client/commit/a407471b14349b8c08018196041568f2a35f8d4f
feat(ideahub): update the api https://github.com/googleapis/google-api-python-client/commit/c6b0d83940f238b1330896240492e8db397dcd15
fix(keep): update the api https://github.com/googleapis/google-api-python-client/commit/08fee732e96d3220e624c8fca7b8a9b0c0bcb146
feat(managedidentities): update the api https://github.com/googleapis/google-api-python-client/commit/863b333da7848029fd1614fd48b46cfbe12afcd5
feat(memcache): update the api https://github.com/googleapis/google-api-python-client/commit/17dc001e4649f54944066ce153e3c552c850a146
feat(metastore): update the api https://github.com/googleapis/google-api-python-client/commit/f3a76c9359babc48cc0b76ce7e3be0711ba028ae
feat(slides): update the api https://github.com/googleapis/google-api-python-client/commit/314d61b9ef8c5c30f9756462504dc0df92284cb2
feat(sqladmin): update the api https://github.com/googleapis/google-api-python-client/commit/62784e0b1b5752b480afe1ddd77dcf412bb35dbb
feat(tpu): update the api https://github.com/googleapis/google-api-python-client/commit/16bf712cca4a393d96e4135de3d02e5005051b6d
feat(youtube): update the api https://github.com/googleapis/google-api-python-client/commit/ec21dff96d9538ad6c7f9b318eca88178533aa95
diff --git a/docs/dyn/serviceusage_v1.services.html b/docs/dyn/serviceusage_v1.services.html
index ade9c42..83b09da 100644
--- a/docs/dyn/serviceusage_v1.services.html
+++ b/docs/dyn/serviceusage_v1.services.html
@@ -242,7 +242,7 @@
           "overview": "A String", # Declares a single overview page. For example: documentation: summary: ... overview: (== include overview.md ==) This is a shortcut for the following declaration (using pages style): documentation: summary: ... pages: - name: Overview content: (== include overview.md ==) Note: you cannot specify both `overview` field and `pages` field.
           "pages": [ # The top level pages for the documentation set.
             { # Represents a documentation page. A page can contain subpages to represent nested documentation set structure.
-              "content": "A String", # The Markdown content of the page. You can use (== include {path} ==) to include content from a Markdown file.
+              "content": "A String", # The Markdown content of the page. You can use (== include {path} ==) to include content from a Markdown file. The content can be used to produce the documentation page such as HTML format page.
               "name": "A String", # The name of the page. It will be used as an identity of the page to generate URI of the page, text of the link to this page in navigation, etc. The full page name (start from the root page name to this page concatenated with `.`) can be used as reference to the page in your documentation. For example: pages: - name: Tutorial content: (== include tutorial.md ==) subpages: - name: Java content: (== include tutorial_java.md ==) You can reference `Java` page using Markdown reference link syntax: `Java`.
               "subpages": [ # Subpages of this page. The order of subpages specified here will be honored in the generated docset.
                 # Object with schema name: Page
@@ -252,12 +252,12 @@
           "rules": [ # A list of documentation rules that apply to individual API elements. **NOTE:** All service configuration rules follow "last one wins" order.
             { # A documentation rule provides information about individual API elements.
               "deprecationDescription": "A String", # Deprecation description of the selected element(s). It can be provided if an element is marked as `deprecated`.
-              "description": "A String", # Description of the selected API(s).
-              "selector": "A String", # The selector is a comma-separated list of patterns. Each pattern is a qualified name of the element which may end in "*", indicating a wildcard. Wildcards are only allowed at the end and for a whole component of the qualified name, i.e. "foo.*" is ok, but not "foo.b*" or "foo.*.bar". A wildcard will match one or more components. To specify a default for all applicable elements, the whole pattern "*" is used.
+              "description": "A String", # The description is the comment in front of the selected proto element, such as a message, a method, a 'service' definition, or a field.
+              "selector": "A String", # The selector is a comma-separated list of patterns for any element such as a method, a field, an enum value. Each pattern is a qualified name of the element which may end in "*", indicating a wildcard. Wildcards are only allowed at the end and for a whole component of the qualified name, i.e. "foo.*" is ok, but not "foo.b*" or "foo.*.bar". A wildcard will match one or more components. To specify a default for all applicable elements, the whole pattern "*" is used.
             },
           ],
           "serviceRootUrl": "A String", # Specifies the service root url if the default one (the service name from the yaml file) is not suitable. This can be seen in any fully specified service urls as well as sections that show a base that other urls are relative to.
-          "summary": "A String", # A short summary of what the service does. Can only be provided by plain text.
+          "summary": "A String", # A short description of what the service does. The summary must be plain text. It becomes the overview of the service displayed in Google Cloud Console. NOTE: This field is equivalent to the standard field `description`.
         },
         "endpoints": [ # Configuration for network endpoints. Contains only the names and aliases of the endpoints.
           { # `Endpoint` describes a network address of a service that serves a set of APIs. It is commonly known as a service endpoint. A service may expose any number of service endpoints, and all service endpoints share the same service definition, such as quota limits and monitoring metrics. Example: type: google.api.Service name: library-example.googleapis.com endpoints: # Declares network address `https://library-example.googleapis.com` # for service `library-example.googleapis.com`. The `https` scheme # is implicit for all service endpoints. Other schemes may be # supported in the future. - name: library-example.googleapis.com allow_cors: false - name: content-staging-library-example.googleapis.com # Allows HTTP OPTIONS calls to be passed to the API frontend, for it # to decide whether the subsequent cross-origin request is allowed # to proceed. allow_cors: true
@@ -535,7 +535,7 @@
       "overview": "A String", # Declares a single overview page. For example: documentation: summary: ... overview: (== include overview.md ==) This is a shortcut for the following declaration (using pages style): documentation: summary: ... pages: - name: Overview content: (== include overview.md ==) Note: you cannot specify both `overview` field and `pages` field.
       "pages": [ # The top level pages for the documentation set.
         { # Represents a documentation page. A page can contain subpages to represent nested documentation set structure.
-          "content": "A String", # The Markdown content of the page. You can use (== include {path} ==) to include content from a Markdown file.
+          "content": "A String", # The Markdown content of the page. You can use (== include {path} ==) to include content from a Markdown file. The content can be used to produce the documentation page such as HTML format page.
           "name": "A String", # The name of the page. It will be used as an identity of the page to generate URI of the page, text of the link to this page in navigation, etc. The full page name (start from the root page name to this page concatenated with `.`) can be used as reference to the page in your documentation. For example: pages: - name: Tutorial content: (== include tutorial.md ==) subpages: - name: Java content: (== include tutorial_java.md ==) You can reference `Java` page using Markdown reference link syntax: `Java`.
           "subpages": [ # Subpages of this page. The order of subpages specified here will be honored in the generated docset.
             # Object with schema name: Page
@@ -545,12 +545,12 @@
       "rules": [ # A list of documentation rules that apply to individual API elements. **NOTE:** All service configuration rules follow "last one wins" order.
         { # A documentation rule provides information about individual API elements.
           "deprecationDescription": "A String", # Deprecation description of the selected element(s). It can be provided if an element is marked as `deprecated`.
-          "description": "A String", # Description of the selected API(s).
-          "selector": "A String", # The selector is a comma-separated list of patterns. Each pattern is a qualified name of the element which may end in "*", indicating a wildcard. Wildcards are only allowed at the end and for a whole component of the qualified name, i.e. "foo.*" is ok, but not "foo.b*" or "foo.*.bar". A wildcard will match one or more components. To specify a default for all applicable elements, the whole pattern "*" is used.
+          "description": "A String", # The description is the comment in front of the selected proto element, such as a message, a method, a 'service' definition, or a field.
+          "selector": "A String", # The selector is a comma-separated list of patterns for any element such as a method, a field, an enum value. Each pattern is a qualified name of the element which may end in "*", indicating a wildcard. Wildcards are only allowed at the end and for a whole component of the qualified name, i.e. "foo.*" is ok, but not "foo.b*" or "foo.*.bar". A wildcard will match one or more components. To specify a default for all applicable elements, the whole pattern "*" is used.
         },
       ],
       "serviceRootUrl": "A String", # Specifies the service root url if the default one (the service name from the yaml file) is not suitable. This can be seen in any fully specified service urls as well as sections that show a base that other urls are relative to.
-      "summary": "A String", # A short summary of what the service does. Can only be provided by plain text.
+      "summary": "A String", # A short description of what the service does. The summary must be plain text. It becomes the overview of the service displayed in Google Cloud Console. NOTE: This field is equivalent to the standard field `description`.
     },
     "endpoints": [ # Configuration for network endpoints. Contains only the names and aliases of the endpoints.
       { # `Endpoint` describes a network address of a service that serves a set of APIs. It is commonly known as a service endpoint. A service may expose any number of service endpoints, and all service endpoints share the same service definition, such as quota limits and monitoring metrics. Example: type: google.api.Service name: library-example.googleapis.com endpoints: # Declares network address `https://library-example.googleapis.com` # for service `library-example.googleapis.com`. The `https` scheme # is implicit for all service endpoints. Other schemes may be # supported in the future. - name: library-example.googleapis.com allow_cors: false - name: content-staging-library-example.googleapis.com # Allows HTTP OPTIONS calls to be passed to the API frontend, for it # to decide whether the subsequent cross-origin request is allowed # to proceed. allow_cors: true
@@ -743,7 +743,7 @@
           "overview": "A String", # Declares a single overview page. For example: documentation: summary: ... overview: (== include overview.md ==) This is a shortcut for the following declaration (using pages style): documentation: summary: ... pages: - name: Overview content: (== include overview.md ==) Note: you cannot specify both `overview` field and `pages` field.
           "pages": [ # The top level pages for the documentation set.
             { # Represents a documentation page. A page can contain subpages to represent nested documentation set structure.
-              "content": "A String", # The Markdown content of the page. You can use (== include {path} ==) to include content from a Markdown file.
+              "content": "A String", # The Markdown content of the page. You can use (== include {path} ==) to include content from a Markdown file. The content can be used to produce the documentation page such as HTML format page.
               "name": "A String", # The name of the page. It will be used as an identity of the page to generate URI of the page, text of the link to this page in navigation, etc. The full page name (start from the root page name to this page concatenated with `.`) can be used as reference to the page in your documentation. For example: pages: - name: Tutorial content: (== include tutorial.md ==) subpages: - name: Java content: (== include tutorial_java.md ==) You can reference `Java` page using Markdown reference link syntax: `Java`.
               "subpages": [ # Subpages of this page. The order of subpages specified here will be honored in the generated docset.
                 # Object with schema name: Page
@@ -753,12 +753,12 @@
           "rules": [ # A list of documentation rules that apply to individual API elements. **NOTE:** All service configuration rules follow "last one wins" order.
             { # A documentation rule provides information about individual API elements.
               "deprecationDescription": "A String", # Deprecation description of the selected element(s). It can be provided if an element is marked as `deprecated`.
-              "description": "A String", # Description of the selected API(s).
-              "selector": "A String", # The selector is a comma-separated list of patterns. Each pattern is a qualified name of the element which may end in "*", indicating a wildcard. Wildcards are only allowed at the end and for a whole component of the qualified name, i.e. "foo.*" is ok, but not "foo.b*" or "foo.*.bar". A wildcard will match one or more components. To specify a default for all applicable elements, the whole pattern "*" is used.
+              "description": "A String", # The description is the comment in front of the selected proto element, such as a message, a method, a 'service' definition, or a field.
+              "selector": "A String", # The selector is a comma-separated list of patterns for any element such as a method, a field, an enum value. Each pattern is a qualified name of the element which may end in "*", indicating a wildcard. Wildcards are only allowed at the end and for a whole component of the qualified name, i.e. "foo.*" is ok, but not "foo.b*" or "foo.*.bar". A wildcard will match one or more components. To specify a default for all applicable elements, the whole pattern "*" is used.
             },
           ],
           "serviceRootUrl": "A String", # Specifies the service root url if the default one (the service name from the yaml file) is not suitable. This can be seen in any fully specified service urls as well as sections that show a base that other urls are relative to.
-          "summary": "A String", # A short summary of what the service does. Can only be provided by plain text.
+          "summary": "A String", # A short description of what the service does. The summary must be plain text. It becomes the overview of the service displayed in Google Cloud Console. NOTE: This field is equivalent to the standard field `description`.
         },
         "endpoints": [ # Configuration for network endpoints. Contains only the names and aliases of the endpoints.
           { # `Endpoint` describes a network address of a service that serves a set of APIs. It is commonly known as a service endpoint. A service may expose any number of service endpoints, and all service endpoints share the same service definition, such as quota limits and monitoring metrics. Example: type: google.api.Service name: library-example.googleapis.com endpoints: # Declares network address `https://library-example.googleapis.com` # for service `library-example.googleapis.com`. The `https` scheme # is implicit for all service endpoints. Other schemes may be # supported in the future. - name: library-example.googleapis.com allow_cors: false - name: content-staging-library-example.googleapis.com # Allows HTTP OPTIONS calls to be passed to the API frontend, for it # to decide whether the subsequent cross-origin request is allowed # to proceed. allow_cors: true