Let tox build wheels for coverage

Test against manylinux wheels

Defer Python 3.10 support

CPython 3.10 is requiring Cython 3, which makes palace fail to compile.

Support Python 3.10

Correct string quoting

Flatten CI/CD

Use real Protocol for Python < 3.8

Also fix a minor typing mistake

Use PyData Sphinx theme

The documentation structure is reworked to best suit the theme.

Update API reference URL

Update docs to reflect migration to SourceHut

Documentation is now hosted by GitLab Pages.

Fix twine invocation

Employ builds.sr.ht

Build wheels for CPython 3.9 and manylinux aarch64

Write tutorial for source effect

Continue stabbing at GH-93

s/Notes/Note/

Use RTD theme for HTML documentation (fix GH-119)

Use peaceiris/actions-gh-pages for docs deploy

Follow up on GH-116

* Include docs in source distributions
* Prevent docs deploy job from failing when there's nothing to commit

Interlink backquoted objects in docstring

Create FUNDING.yml