[clang] Add retrieval of unary operator spelling and python bindings (PR #219983)

[Vlad Serebrennikov via cfe-commits]

Endilll wrote:

@ItsRumo can you make your email public, as per our [Developer Policy](https://llvm.org/docs/DeveloperPolicy.html#email-addresses)? Let me know when you've done that, and I'll merge this PR.

https://github.com/llvm/llvm-project/pull/219983