[clang] [libclang/python] Fix evaluation of the unsigned enumeration values, #108766 (PR #108769)

[Dmitry Fursov via cfe-commits]

fursov wrote:

Sorry, I'm not familiar with the process (this is my first PR on github) - how the change gets now to the repo? Someone from llvm-project should push it?

https://github.com/llvm/llvm-project/pull/108769