Port various auto-decorating floors from Eris

code/game/turfs/simulated/floor.dm

@@ -33,9 +33,7 @@
 	var/lava = 0
 
 /turf/simulated/floor/is_plating()
-	if(!flooring || flooring.is_plating)
-		return TRUE
-	return FALSE
+	return (!flooring || flooring.is_plating)
 
 /turf/simulated/floor/Initialize(mapload, floortype)
 	. = ..()

code/game/turfs/simulated/floor_types_eris.dm

@@ -957,6 +957,7 @@
 	name = "underplating"
 	icon_state = "under"
 	initial_flooring = /decl/flooring/reinforced/plating/under
+
 /turf/simulated/floor/plating/eris/under/airless
 	oxygen = 0
 	nitrogen = 0