There were numerous bad references, anchor names, filenames, typos,
formatting, syntax errors, missing terms, conflicts, and other errors in
the documentation that have accumulated over the release.

This addresses these by fixing up the naming and references across the
codebase and addressing all the bad references I could find. New terms
and missing signal docstrings were added as well.

Along with this, I've fixed the release notes to include the current
year in the copyright.

Built the docs and saw a lot fewer errors.
Not eveything is fixed. Some are a bit hard to fix (seem to be Sphinx

autodoc bugs conflicting with Django's model support), and some

originate in Djblets. This is at least a good start, and are more

crucial for the 2.5 RC 1 release notes.