Get rid of force_mintrap, allow passing flags to mintrap

It uses the same flags as dotrap, so simulate force_mintrap
by passing FORCETRAP flag.

src/uhitm.c

@@ -1365,7 +1365,7 @@ hmon_hitmon(
                 Sprintf(withwhat, " with %s", yname(obj));
             pline("%s divides as you hit it%s!", Monnam(mon), withwhat);
             hittxt = TRUE;
-            (void) mintrap(mclone);
+            (void) mintrap(mclone, NO_TRAP_FLAGS);
         }
     }