[clang] [Clang][HLSL][DebugInfo] Emit dx.source metadata nodes (PR #199689)

[Aaron Ballman via cfe-commits]

https://github.com/AaronBallman commented:

Removing my request for changes, but I don't feel confident in reviewing HLSL enough to approve (I leave it to the HLSL maintainers for final sign-off). I don't know if the failed precommit CI is related to this PR or not.

https://github.com/llvm/llvm-project/pull/199689