[clang] Support HLSL matrix initializers (PR #160960)

[Farzon Lotfi via cfe-commits]

farzonl wrote:

> I think this approach probably needs some adjustment. HLSL allows constructor-like syntax but it behaves the same way the HLSL initializer list syntax does, so matrix initialization should be done through SemaHLSL’s initialization list handling.

Will look into this thanks for spec reference. If I do things through SemaHLSL for matrices how do we want to support this request?
https://github.com/llvm/llvm-project/pull/160960#discussion_r2384246323

Also why did we do vectors via SemaInit? Are vectors also using SemaHLSL’s initialization list handling? I'm assuming if so it came after the commit linked below

https://github.com/llvm/llvm-project/commit/9f499d9d73edfc818978c64eb24b8d2d34995d76



https://github.com/llvm/llvm-project/pull/160960