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/zap.c

@@ -1873,7 +1873,7 @@ stone_to_flesh_obj(struct obj *obj)
     case ROCK_CLASS: /* boulders and statues */
     case TOOL_CLASS: /* figurines */
         if (obj->otyp == BOULDER) {
-            obj = poly_obj(obj, HUGE_CHUNK_OF_MEAT);
+            obj = poly_obj(obj, ENORMOUS_MEATBALL);
             smell = TRUE;
         } else if (obj->otyp == STATUE || obj->otyp == FIGURINE) {
             ptr = &mons[obj->corpsenm];