[clang] [Matrix][HLSL] Add codgen support for Matrix Layout keywords (PR #198887)

[Justin Bogner via cfe-commits]

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

The PR title has a typo (s/codgen/codegen) and the PR description has some weird indentation (which shows up as a code block in the github UI) - Please fix these for the commit message.

Otherwise, LGTM with a few nitpicks. 


https://github.com/llvm/llvm-project/pull/198887