[clang] [libclang/python] Add strict typing to clang Python bindings (#76664) (PR #78114)

[Vlad Serebrennikov via cfe-commits]

https://github.com/Endilll commented:

`+471 −397` is still a bit too much to my liking. I think there's a way for further splitting. I left comments about possible direction.

https://github.com/llvm/llvm-project/pull/78114