Fix \seepep handling -- correct URL to the online PEP repository on SF is
now generated. (SF bug #129692.)
Patch from Anthon van der Neut <anthon@mnt.org>:
Work around the removal of content-less paired tags used for name
anchors in some places. (SF bug #116008.)
Move some class attributes from an artificial SPAN element to otherwise
"useful" elements that are being generated anyway. Added the class
"versionnote", used for \deprecated, \versionadded, \versionchanged.