Fix method doc signatures for multiline required parameters (#374)

* Fix method doc signatures for multiline required parameters.

Existing doc generator failed to recognize parameters as required when parameter descriptions
extended over more than one line. Besides presenting incorrect information, resulting
inconsistencies broke checks for automated sample generation.

* Regen docs
diff --git a/docs/dyn/spanner_v1.projects.instances.html b/docs/dyn/spanner_v1.projects.instances.html
index 70fcf06..8bccf28 100644
--- a/docs/dyn/spanner_v1.projects.instances.html
+++ b/docs/dyn/spanner_v1.projects.instances.html
@@ -85,25 +85,25 @@
 <p class="firstline">Returns the operations Resource.</p>
 
 <p class="toc_element">
-  <code><a href="#create">create(parent=None, body, x__xgafv=None)</a></code></p>
+  <code><a href="#create">create(parent, body, x__xgafv=None)</a></code></p>
 <p class="firstline">Creates an instance and begins preparing it to begin serving. The</p>
 <p class="toc_element">
-  <code><a href="#delete">delete(name=None, x__xgafv=None)</a></code></p>
+  <code><a href="#delete">delete(name, x__xgafv=None)</a></code></p>
 <p class="firstline">Deletes an instance.</p>
 <p class="toc_element">
-  <code><a href="#get">get(name=None, x__xgafv=None)</a></code></p>
+  <code><a href="#get">get(name, x__xgafv=None)</a></code></p>
 <p class="firstline">Gets information about a particular instance.</p>
 <p class="toc_element">
   <code><a href="#getIamPolicy">getIamPolicy(resource, body, x__xgafv=None)</a></code></p>
 <p class="firstline">Gets the access control policy for an instance resource. Returns an empty</p>
 <p class="toc_element">
-  <code><a href="#list">list(parent=None, pageSize=None, filter=None, pageToken=None, x__xgafv=None)</a></code></p>
+  <code><a href="#list">list(parent, pageSize=None, filter=None, pageToken=None, x__xgafv=None)</a></code></p>
 <p class="firstline">Lists all instances in the given project.</p>
 <p class="toc_element">
   <code><a href="#list_next">list_next(previous_request, previous_response)</a></code></p>
 <p class="firstline">Retrieves the next page of results.</p>
 <p class="toc_element">
-  <code><a href="#patch">patch(name=None, body, x__xgafv=None)</a></code></p>
+  <code><a href="#patch">patch(name, body, x__xgafv=None)</a></code></p>
 <p class="firstline">Updates an instance, and begins allocating or releasing resources</p>
 <p class="toc_element">
   <code><a href="#setIamPolicy">setIamPolicy(resource, body, x__xgafv=None)</a></code></p>
@@ -113,7 +113,7 @@
 <p class="firstline">Returns permissions that the caller has on the specified instance resource.</p>
 <h3>Method Details</h3>
 <div class="method">
-    <code class="details" id="create">create(parent=None, body, x__xgafv=None)</code>
+    <code class="details" id="create">create(parent, body, x__xgafv=None)</code>
   <pre>Creates an instance and begins preparing it to begin serving. The
 returned long-running operation
 can be used to track the progress of preparing the new
@@ -302,7 +302,7 @@
 </div>
 
 <div class="method">
-    <code class="details" id="delete">delete(name=None, x__xgafv=None)</code>
+    <code class="details" id="delete">delete(name, x__xgafv=None)</code>
   <pre>Deletes an instance.
 
 Immediately upon completion of the request:
@@ -339,7 +339,7 @@
 </div>
 
 <div class="method">
-    <code class="details" id="get">get(name=None, x__xgafv=None)</code>
+    <code class="details" id="get">get(name, x__xgafv=None)</code>
   <pre>Gets information about a particular instance.
 
 Args:
@@ -622,7 +622,7 @@
 </div>
 
 <div class="method">
-    <code class="details" id="list">list(parent=None, pageSize=None, filter=None, pageToken=None, x__xgafv=None)</code>
+    <code class="details" id="list">list(parent, pageSize=None, filter=None, pageToken=None, x__xgafv=None)</code>
   <pre>Lists all instances in the given project.
 
 Args:
@@ -725,7 +725,7 @@
 </div>
 
 <div class="method">
-    <code class="details" id="patch">patch(name=None, body, x__xgafv=None)</code>
+    <code class="details" id="patch">patch(name, body, x__xgafv=None)</code>
   <pre>Updates an instance, and begins allocating or releasing resources
 as requested. The returned long-running
 operation can be used to track the