[clang] [libclang/python] Derive library function types from annotations (PR #142120)

[Vlad Serebrennikov via cfe-commits]

Endilll wrote:

There are useful suggestions in the comments of https://github.com/python/mypy/issues/7540, but it's sad that we need to resort to something like this 10 years after type annotations became a thing.

https://github.com/llvm/llvm-project/pull/142120