rename "huge chunk of meat" to "enormous meatball"

Pull request #607 by Vivit-R proposed renaming "huge chunk of meat"
to "giant meatball" to better reflect the similarity to meatball.
But an object name that contains a monster name prefix requires extra
work in the wishing code.  I considered "huge meatball" which retains
more of the original name but decided to go with "enormous meatball"
becaues it seems more evocative.

Supersedes #607
Closes #607

src/dog.c

@@ -954,7 +954,7 @@ dogfood(struct monst *mon, struct obj *obj)
         case MEATBALL:
         case MEAT_RING:
         case MEAT_STICK:
-        case HUGE_CHUNK_OF_MEAT:
+        case ENORMOUS_MEATBALL:
             return carni ? DOGFOOD : MANFOOD;
         case EGG:
             return carni ? CADAVER : MANFOOD;