[clang] [libclang/python] Fix some type errors, add type annotations (PR #98745)

[Jannick Kremer via cfe-commits]

DeinAlptraum wrote:

@Endilll I am once again asking for your support
This PR collects several of the changes towards #78114 that I assume might need some discussion. I tried to leave PR comments with explanations in each of those places.
@boomanaiden154 @linux4life798 review from you would also be appreciated!

https://github.com/llvm/llvm-project/pull/98745