[Bug libstdc++/104299] Doc: stdio is not the only option in --enable-cstdio=XXX

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104299

--- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Fixed on trunk and gcc-13 so far.