Splits placeontop proc (#79702)

## About The Pull Request
I find the proc hard to read honestly. There's no reason we can't split
this into two functions - the secondary functionality is used only once,
in reader.dmm.
## Why It's Good For The Game
Code improvement
Glorious snake case
## Changelog
N/A nothing player facing

---------

Co-authored-by: san7890 <34697715+san7890@users.noreply.github.com>

code/game/objects/effects/effect_system/fluid_spread/effects_foam.dm

@@ -361,7 +361,7 @@
 				return
 			to_chat(user, span_notice("You add the plating."))
 			var/turf/T = get_turf(src)
-			T.PlaceOnTop(/turf/closed/wall/metal_foam_base)
+			T.place_on_top(/turf/closed/wall/metal_foam_base)
 			transfer_fingerprints_to(T)
 			qdel(src)
 		return
@@ -393,7 +393,7 @@
 /obj/effect/particle_effect/fluid/foam/metal/smart/make_result() //Smart foam adheres to area borders for walls
 	var/turf/open/location = loc
 	if(isspaceturf(location))
-		location.PlaceOnTop(/turf/open/floor/plating/foam)
+		location.place_on_top(/turf/open/floor/plating/foam)
 
 	for(var/cardinal in GLOB.cardinals)
 		var/turf/cardinal_turf = get_step(location, cardinal)