[clang] [clang][python] Fix get_includes documentation (PR #222239)

[Jannick Kremer via cfe-commits]

DeinAlptraum wrote:

Are you sure this is correct? 🤔 
We have a test that pretty much asserts the current doc behavior here:
https://github.com/llvm/llvm-project/blob/main/clang/bindings/python/tests/cindex/test_translation_unit.py#L144-L160
(translation unit created from "include.cpp", which we can see is returend as the first element of the first tuple in the results)

cc @Endilll 

https://github.com/llvm/llvm-project/pull/222239