[clang] [clang][Sema] Improve template argument deduction diagnostic (PR #122754)

[Aidan Goldfarb via cfe-commits]

================
@@ -649,15 +649,15 @@ namespace cwg241 { // cwg241: 9
     A::g<3>(b);
     C::f<3>(b);
     // expected-error at -1 {{no matching function for call to 'f'}}
-    //   expected-note@#cwg241-C-f {{candidate template ignored: invalid explicitly-specified argument for template parameter 'T'}}
+    //   expected-note@#cwg241-C-f {{candidate template ignored: invalid explicitly-specified argument for template parameter 'T': could not convert '3' from 'int' to class 'T' (expected a class, but got '3')}}
----------------
AidanGoldfarb wrote:

What you suggested is more like what GCC does, and I have updated it in my last patch, thanks!

https://github.com/llvm/llvm-project/pull/122754