Update Map Room (Incursion) Description

Since the Incursion league, the map room states that it 'Contains chests full of maps.' The truth is that it contains 1 chest per level of the room, which means that at level 1 (Surveyor's study) it contains 1 chest with maps.

The description fits other rooms with multiple chests, but with the new explosives room, it now states it 'Contains (one/two/three) Sealed Coffer(s)' based on its level. The map room should reflect the same I think.