[clang] [Clang] Emit a diagnostic note at the class declaration when the method definition does not match any declaration. (PR #110638)

[Vlad Serebrennikov via cfe-commits]

================
@@ -102,12 +102,13 @@ namespace MultilevelSpecialization {
   // default argument -- how far back do we look when determining whether a
   // parameter was expanded from a pack?
   //   -- zygoloid 2020-06-02
-  template<typename ...T> struct B {
+  template<typename ...T> struct B { // #defined-here
----------------
Endilll wrote:

```suggestion
  template<typename ...T> struct B { // #cwg2233-B
```

https://github.com/llvm/llvm-project/pull/110638