[clang] [llvm] [HLSL][DXIL] Implement WaveGetLaneIndex Intrinsic (PR #111576)

[Greg Roth via cfe-commits]

https://github.com/pow2clk commented:

Small typo in description: 
"IntrinscsDirectX"

Looks good, but I have a question about the SPIRV part.

https://github.com/llvm/llvm-project/pull/111576