Remove references to no longer useful diagnostic group 'ambiguousFunctionDecl'. This has been a noop since June 2017
@@ -363,7 +363,6 @@ require as a parameter a `WARNCLASS` warning class name. The following
names are valid warning class names:
* ``accessControls``
-* ``ambiguousFunctionDecl``
* ``checkRegExp``
* ``checkTypes``
* ``checkVars``
