[clang] [clang][Python] Apply type annotations to Python (PR #173845)

[Vlad Serebrennikov via cfe-commits]

https://github.com/Endilll requested changes to this pull request.

> @Endilll is the concern with annotating variables? I do think generally speaking including this information is helpful for IDEs and in other places and generally conveys intent the most clearly.

The comment I made two weeks ago could be taken quite literally. I left a full review if that helps.

https://github.com/llvm/llvm-project/pull/173845