[llvm] [C API] Add getters for Target Extension Types to C API (PR #71291)

[Benji Smith via llvm-commits]

Benjins wrote:

> This needs mentioning in the release notes.

Gotcha. I've added a section to the release notes for it in another commit: let me know if it's okay

https://github.com/llvm/llvm-project/pull/71291