[clang] [HLSL][Matrix] Add support for single subscript accessor (PR #170779)

[Helena Kotas via cfe-commits]

================
@@ -165,7 +165,7 @@ namespace clang {
     /// Objective-C method calls.
     OK_ObjCSubscript,
 
-    /// A matrix component is a single element of a matrix.
+    /// A matrix component is a single element or range of elements on a matrix.
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hekota wrote:

```suggestion
    /// A matrix component is a single element or range of elements of a matrix.
```

https://github.com/llvm/llvm-project/pull/170779