Release 1.1 tracking: Verification, changelog entries

[benjaoming]

For a list of open issues, see the 1.1 milestone: https://github.com/readthedocs/sphinx_rtd_theme/issues?q=is%3Aopen+is%3Aissue+milestone%3A1.1

This is a meta-level issue to track that new PRs for 1.1 have a little extra verification since CI tests have had difficulties

• Nicer styles for <kbd> #967 and Tune kbd selectors #1330 - check with html4 writer the writer works, but the theme doesn't respect it and emits an html5 doctype regardless of the html4_writer=True config value.
• Use static setuptools metadata #1116 - how old versions of pip accept setup.cfg? Edit: it's setuptools that generates the release package that's responsible for reading it, which it can do since 2016
• Fix #1078: Citation not styled properly #1080 - changelog entry missing
• Release 1.1 with upper bounds on dependencies #1309 - changelog entry missing
• Fixes #289: Inconsistent table typography sizing #1215 - changelog entry missing
• Add Python 3.10 support #1334 - changelog entry missing
• Fix definition lists inside api docs #1084 - changelog entry missing
• Update layout.html to support a sphinx version that is not three-integers #1345 - changelog entry missing

Updates incoming for every PR that needs verification + changelog entry.

[benjaoming]

Released!