Allow groundworms/queens to be hit with maces, add failure to hit msg.

As title says, allow maces to hit groundworms and queens in addition to larvae, also add a message if the current/no weapon cannot hit the groundworm so newbies know they can't hit it. I was tempted to expand the message with a reference to perhaps using a blunt weapon, but I think most players would already try a different weapon, or ask other players why it didn't work.