Allow nurses heal attack when wielding a non-weapon/weaptool

This matches the nurses' hitting behavior with their chatting messages.

Chatting to them suggested that the heal attack would happen but the check in
mhitu.c was just for wielding anything.

This opens up the possibility of a YAFM in MS_NURSE when wielding something
that allos the heal attack to proceed.  But I couldn't come up with a good
one.

src/mhitu.c

@@ -1508,7 +1508,9 @@ register struct attack *mattk;
             hitmsg(mtmp, mattk);
             break;
         }
-        if (!uwep && !uarmu && !uarm && !uarmc
+        /* weapon check should match the one in sounds.c for MS_NURSE */
+        if (!(uwep && (uwep->oclass == WEAPON_CLASS || is_weptool(uwep)))
+            && !uarmu && !uarm && !uarmc
             && !uarms && !uarmg && !uarmf && !uarmh) {
             boolean goaway = FALSE;