gh-151942: Fix all Sphinx nitpicks in the Python 2.4 What's New (GH-153116)

(cherry picked from commit fc9fe14)

Co-authored-by: Stan Ulbrych <stan@python.org>

Author: StanFromIreland

Doc/tools/.nitignore

@@ -33,5 +33,4 @@ Doc/library/xml.sax.reader.rst
 Doc/library/xml.sax.rst
 Doc/library/xmlrpc.client.rst
 Doc/library/xmlrpc.server.rst
-Doc/whatsnew/2.4.rst
 Doc/whatsnew/2.6.rst