[clang] [libclang/python] Improve error reporting of `TranslationUnit` creating functions (PR #102410)

[Jannick Kremer via cfe-commits]

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

LGTM. Thanks for adding better error handling!
@Endilll do you also want to take a look at this before it is merged? Otherwise, this is good to go imo.

https://github.com/llvm/llvm-project/pull/102410