* ensure our docs build cleanly with sphinx-5
* adapt to the API change in sphinx 5
while keeping compatibility with <5
* get rid of the extra colons in field lists
The CSS (changed in bca76b8f) was removing space between actual paragraphs in
lists. This was intended to address excess padding in changelogs, but that is
resolved here by removing blank lines surrounding nested lists. This still
displays properly on GitHub/Reddit and presumably other Markdown implementations
as well.
This mainly involved tweaking a few filenames and configuration paths to
allow consistency in all scenarios. It cleared up a few errors in the
process too!
I also clarified the placement of the LICENSE file, and finished
configuring the Alabaster style. This required moving some stuff out of
the CMake system to conf.py to avoid later breakage.