[Bug libstdc++/110602] std::format and friends are accessible without std::

[redi at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110602

--- Comment #4 from Jonathan Wakely <redi at gcc dot gnu.org> ---
(In reply to kefu chai from comment #0)
> i also tested clang + libstdc++ and clang + libc++. all of these
> combinations compiles.

That's usually a sign the code is valid.