Regen all docs. (#700)

* Stop recursing if discovery == {}

* Generate docs with 'make docs'.
diff --git a/docs/dyn/gmail_v1.users.threads.html b/docs/dyn/gmail_v1.users.threads.html
index 245e9ab..ce96c73 100644
--- a/docs/dyn/gmail_v1.users.threads.html
+++ b/docs/dyn/gmail_v1.users.threads.html
@@ -184,7 +184,7 @@
     {
     "nextPageToken": "A String", # Page token to retrieve the next page of results in the list.
     "resultSizeEstimate": 42, # Estimated total number of results.
-    "threads": [ # List of threads.
+    "threads": [ # List of threads. Note that each thread resource does not contain a list of messages. The list of messages for a given thread can be fetched using the threads.get method.
       { # A collection of messages representing a conversation.
         "snippet": "A String", # A short part of the message text.
         "messages": [ # The list of messages in the thread.