containers and objects in special level descriptions

On mazelike levels, containers had to be listed before their objects.  But,
for roomfilled levels, containers had to be listed _after_ the objects.  All
our current levels that use containers with objects are mazelike, so I
changed the room behavior, updating the comment in lev_comp.y to match.
Other items/monsters are still processed in reverse on roomfilled special
levels, but I think this is OK.

util/lev_comp.y

@@ -877,7 +877,7 @@ object_detail	: OBJECT_ID object_desc
 		  }
 		| COBJECT_ID object_desc
 		  {
-			/* 1: is contents of next object with 2 */
+			/* 1: is contents of preceeding object with 2 */
 			/* 2: is a container */
 			/* 0: neither */
 			tmpobj[nobj-1]->containment = 2;