* util/grub-install.in: Unify "option requires an argument" message

with similar messages in other files.
	* util/grub-mkconfig.in: Likewise.

util/grub-install.in

@@ -122,7 +122,7 @@ argument () {
   shift
 
   if test $# -eq 0; then
-      gettext_printf "%s: option requires an argument -- \`%s'" "$0" "$opt" 1>&2
+      gettext_printf "%s: option requires an argument -- \`%s'\n" "$0" "$opt" 1>&2
       exit 1
   fi
   echo "$1"