Revert "avoid redraw when there's no change"

This reverts commit 6818e07291.

This broke keys such as ^W to delete-backward-word

dmenu.c

@@ -415,8 +415,7 @@ keypress(XKeyEvent *ev)
 	switch(ksym) {
 	default:
 insert:
-		if (iscntrl((unsigned char)*buf))
-			return;
+		if (!iscntrl(*buf))
 			insert(buf, len);
 		break;
 	case XK_Delete: