Fix references in the webapi docs.

The new version of Sphinx moved such things as xrefs into new "domains"
(namespaces). The generator for webapi docs wasn't specifying the domain for
"ref", so we ended up with blank references. We now use the "std" domain,
which gives us our references back!

docs/manual/_ext/webapidocs.py

@@ -640,8 +640,8 @@ def get_resource_docname(resource, is_list):
 def get_ref_to_doc(refname):
     """Returns a node that links to a document with the given ref name."""
     ref = addnodes.pending_xref(reftype='ref', reftarget=refname,
-                                refcaption=False)
-    ref += nodes.literal(title=refname, classes=['xref'])
+                                refexplicit=False, refdomain='std')
+    ref += nodes.literal(refname, refname, classes=['xref'])
     return ref