nbtree: Correct inaccurate split location comment.

Minor oversight in commit fab25024.

src/backend/access/nbtree/nbtsplitloc.c

@@ -190,7 +190,7 @@ _bt_findsplitloc(Relation rel,
 	Assert(!BTreeTupleIsPosting(newitem));
 
 	/*
-	 * maxsplits should never exceed maxoff because there will be at most as
+	 * nsplits should never exceed maxoff because there will be at most as
 	 * many candidate split points as there are points _between_ tuples, once
 	 * you imagine that the new item is already on the original page (the
 	 * final number of splits may be slightly lower because not all points