Improve descriptions of introspection changes

Several of the introspection changes in Python 3.4 are indirect,
where inspect module changes affected pydoc, and those in turn
affected the help builtin. This update adds versionchanged
notes in the key locations, as well as more coverage in the
What's New document (in particular, a note in the porting
section regarding the expanded domain for inspect.getfullargspec).

Doc/library/functions.rst

@@ -610,6 +610,10 @@ are always available.  They are listed here in alphabetical order.
 
    This function is added to the built-in namespace by the :mod:`site` module.
 
+   .. versionchanged:: 3.4
+      Changes to :mod:`pydoc` and :mod:`inspect` mean that the reported
+      signatures for callables are now more comprehensive and consistent.
+
 
 .. function:: hex(x)
 

Doc/library/inspect.rst

@@ -729,6 +729,11 @@ Classes and functions
       Consider using the new :ref:`Signature Object <inspect-signature-object>`
       interface, which provides a better way of introspecting functions.
 
+   .. versionchanged:: 3.4
+      This function is now based on :func:`signature`, but still ignores
+      ``__wrapped__`` attributes and includes the already bound first
+      parameter in the signature output for bound methods.
+
 
 .. function:: getargvalues(frame)
 

Doc/library/pydoc.rst

@@ -84,3 +84,8 @@ Reference Manual pages.
 
 .. versionchanged:: 3.2
    Added the ``-b`` option, deprecated the ``-g`` option.
+
+.. versionchanged:: 3.4
+   :mod:`pydoc` now uses :func:`inspect.signature` rather than
+   :func:`inspect.getfullargspec` to extract signature information from
+   callables.