doc: For module names, use texinfo markup @code{} or @samp{}. * doc/alloca.texi: Mark gnulib module names with @code. * doc/alloca-opt.texi: Likewise. * doc/quote.texi: Likewise. * doc/posix-functions/freopen.texi: Likewise. * doc/posix-functions/open.texi: Likewise. * doc/posix-functions/readlink.texi: Likewise. * doc/posix-functions/readlinkat.texi: Likewise. * doc/posix-functions/stdout.texi: Likewise. * doc/posix-functions/stderr.texi: Likewise. * doc/posix-functions/unlink.texi: Likewise. * doc/posix-functions/unlinkat.texi: Likewise. * doc/posix-functions/utime.texi: Likewise. * doc/posix-functions/utimensat.texi: Likewise. * doc/posix-functions/utimes.texi: Likewise. * doc/posix-headers/stdint.texi: Likewise. * doc/glibc-functions/futimesat.texi: Likewise. * doc/glibc-functions/lutimes.texi: Likewise. * doc/glibc-functions/memmem.texi: Likewise.