[clang] [clang] fix matching of nested template template parameters (PR #130447)

[via cfe-commits]

================
@@ -11363,14 +11363,16 @@ class Sema final : public SemaBase {
 
   /// The context in which we are checking a template parameter list.
   enum TemplateParamListContext {
-    TPC_ClassTemplate,
-    TPC_VarTemplate,
+    // For this context, Class, Variable, TypeAlias, and non-pack Template
+    // Template Parameters are the same.
----------------
cor3ntin wrote:

```suggestion
    // Template Parameters are treated uniformly.
```

https://github.com/llvm/llvm-project/pull/130447