[Bug fortran/110595] Documentation: typo in the docs for -Wmissing-include-dirs

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110595

--- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> ---
I think this would be better, but a fortran maintainer should confirm that:

For Fortran, it is partially enabled by default, only warning for @option{-I}
and @option{-J}."