Add wsproto.Connection reference

[MtkN1]

Hello! I have made some minor document corrections.

Summary

1. Add wsproto.Connection reference
   wsproto.Connection is described in Post handshake connection, but it is not listed in the API reference in the documentation. It would be useful to see this in the documentation. Added autodoc directives to api.rst and fixed docstrings.

2. Fix Read the Docs build
   While working on the above fix, I noticed that the latest build of Read the Docs for wsproto is failing.

   https://readthedocs.org/projects/wsproto/builds/22942691/

   Problem in your project's configuration. No default configuration file found at repository's root. See https://docs.readthedocs.io/en/stable/config-file/

   It looks like the .readthedocs.yaml file is now required to build Read the Docs ¹. The .readthedocs.yaml file has been added. Also added requirements.txt for the documentation, since the sphinx-rtd-theme is not automatically applied.

   I don't think the Read the docs preview in the pull request is set up, so I built the docs in the fork repository. You can check that here
   https://improved-octo-garbanzo.readthedocs.io/en/latest/api.html#wsproto.Connection

Footnotes

1. https://blog.readthedocs.com/migrate-configuration-v2/ ↩

[MtkN1]

Hello, maintainers. Is it possible to get a review? It is not a high priority :)

[Kriechi]

LGTM, but some minor linting issues and an issue with sdist packaging of the new config file, please see the CI failure log.

[MtkN1]

Oh, sorry. I thought the CI error was unrelated since it was also occurring in the base branch.

I have fixed this. I think the CI that is failing now is the same as the previous pull request (#187 (comment)).