typo in U897 change

in the process of merging my change into the source, the "=" got lost

src/dokick.c

@@ -456,7 +456,7 @@ xchar x, y;
 	    range = range / 3 + 1;	/* {1,2}=>1, {3,4,5}=>2, {6,7,8}=>3 */
 	} else if (Is_airlevel(&u.uz) || Is_waterlevel(&u.uz)) {
 	    /* you're in air, since is_pool did not match */
-	    range + rnd(3);
+	    range += rnd(3);
 	} else {
 	    if (is_ice(x, y)) range += rnd(3),  slide = TRUE;
 	    if (kickobj->greased) range += rnd(3),  slide = TRUE;