[Bug fortran/104888] diagnostics use non-idiomatic '%s'

[roland.illig at gmx dot de via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104888

--- Comment #1 from Roland Illig <roland.illig at gmx dot de> ---
While here:
> expected : at %C

The quotes around the %<:%> are missing.