[clang] [HLSL] Implement output parameter (PR #101083)

[Chris B via cfe-commits]

llvm-beanz wrote:

@rjmccall curious if you have some time to look at this PR. I've made some small changes to extend parameter ABI annotations and write back arguments (used by ObjC) to cover HLSL's odd parameter behaviors.

https://github.com/llvm/llvm-project/pull/101083