Clarify several translatable messages.

grub-core/osdep/aros/config.c

@@ -89,6 +89,6 @@ grub_util_load_config (struct grub_util_config *cfg)
       fclose (f);
     }
   else
-    grub_util_warn (_("cannot open config file `%s': %s"),
+    grub_util_warn (_("cannot open configuration file `%s': %s"),
 		    cfgfile, strerror (errno));
 }