[clang] [libclang/python] Export all enums (PR #100941)

[Vlad Serebrennikov via cfe-commits]

https://github.com/Endilll approved this pull request.

LGTM
I think `__all__` can be made a tuple instead, but it's not necessarily in the scope of this PR.

https://github.com/llvm/llvm-project/pull/100941