[Bug c++/98768] Improve diagnostics for incorrect result type checking "-> Type" in concepts

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98768

--- Comment #2 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Oops! I meant:

  { func() } -> std::same_as<T>;