build: run docs regen in synth.py (#1059)

diff --git a/docs/dyn/smartdevicemanagement_v1.enterprises.structures.rooms.html b/docs/dyn/smartdevicemanagement_v1.enterprises.structures.rooms.html
index e7746b5..5313cf6 100644
--- a/docs/dyn/smartdevicemanagement_v1.enterprises.structures.rooms.html
+++ b/docs/dyn/smartdevicemanagement_v1.enterprises.structures.rooms.html
@@ -139,7 +139,7 @@
         "name": "A String", # Output only. The resource name of the room. For example: "enterprises/XYZ/structures/ABC/rooms/123".
       },
     ],
-    "nextPageToken": "A String", # The pagination token to retrieve the next page of results.
+    "nextPageToken": "A String", # The pagination token to retrieve the next page of results. If this field is omitted, there are no subsequent pages.
   }</pre>
 </div>