Improving type annotations in Sphinx

@JelleZijlstra, @srittau thanks for all your help with the docutils type stubs.

The point of all these PRs is facilitate migrating the venerable Sphinx project from docutils-stubs to types-docutils.

There's a PR for that here - https://github.com/sphinx-doc/sphinx/pull/12012

there's still a number of errors remaining. Some are issues with Sphinx, others with the type annotations themselves.
I wonder if you have any bandwidth to help me get this PR over the line, and get Sphinx using typeshed once and for all?

まず Sphinx の PR #12012 と、そこに記載されている残りのエラーを確認します。docutils-stubs と types-docutils のアノテーションを比較し、どのエラーが Sphinx に属し、どのエラーが型アノテーションに属するのかを判断します。残りのエラーに対処し、Sphinx が typeshed を使用できるようになれば完了です。