[llvm] [DirectX] Updating DXContainer Yaml to represent Root Signature 1.2 (PR #159659)

[Finn Plummer via llvm-commits]

================
@@ -813,6 +822,21 @@ struct DescriptorRange {
   }
 };
 } // namespace v2
+namespace v3 {
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inbelic wrote:

nit:
```suggestion

namespace v3 {
```

https://github.com/llvm/llvm-project/pull/159659