[clang] [llvm] [HLSL][RootSignature] Add `hlsl-rootsig-ver` option to specify root signature version (PR #144813)

[Justin Bogner via cfe-commits]

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@@ -5188,16 +5191,20 @@ class HLSLRootSignatureDecl final
   }
 
   HLSLRootSignatureDecl(DeclContext *DC, SourceLocation Loc, IdentifierInfo *ID,
+                        llvm::dxbc::RootSignatureVersion Verison,
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bogner wrote:

```suggestion
                        llvm::dxbc::RootSignatureVersion Version,
```

https://github.com/llvm/llvm-project/pull/144813