[clang] [clang-tools-extra] [clangd][HLSL] Fix register attribute source range for hover inside arguments (PR #212881)

[Finn Plummer via cfe-commits]

================
@@ -5311,6 +5311,30 @@ TEST(Hover, FunctionParameters) {
   }
 }
 
+TEST(Hover, HLSLRegisterAttributeRange) {
+  Annotations T(R"cpp(
----------------
inbelic wrote:

Should the following supported? If it isn't, is this something we should add?
```suggestion
  Annotations T(R"hlsl(
```

https://github.com/llvm/llvm-project/pull/212881