[Bug fortran/84354] Replace '%qs' with %qs in fortran/decl.c

[fmarchal at perso dot be]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84354

--- Comment #2 from Frederic Marchal <fmarchal at perso dot be> ---
You are right. Only three occurrences of '%qs'.

It looked like more when I translated those messages :-)