swaybar: move mode & mode_pango_markup to bar struct

This distinguishes the binding mode from the distinct config mode, as
well as removing mode_pango_markup from the config struct where it
should not be present.

swaybar/bar.c

@@ -631,4 +631,5 @@ void bar_teardown(struct swaybar *bar) {
 		status_line_free(bar->status);
 	}
 	free(bar->id);
+	free(bar->mode);
 }