Refactors rusted walls and their spawners (#17969)

* refactors rusted walls and their spawners

* tidies this up a bit

* moxian review

* Apply suggestions from code review

Co-authored-by: AffectedArc07 <25063394+AffectedArc07@users.noreply.github.com>
Co-authored-by: moxian <moxian@users.noreply.github.com>

* Update code/game/turfs/simulated/walls.dm

Co-authored-by: moxian <moxian@users.noreply.github.com>

* more things

* Update code/game/turfs/simulated/walls.dm

Co-authored-by: moxian <moxian@users.noreply.github.com>

Co-authored-by: AffectedArc07 <25063394+AffectedArc07@users.noreply.github.com>
Co-authored-by: moxian <moxian@users.noreply.github.com>

code/game/objects/effects/spawners/random_spawners.dm

@@ -61,19 +61,36 @@
 	/datum/nothing = 5,
 	/obj/effect/decal/cleanable/blood/oil = 1)
 
+/obj/effect/spawner/random_spawners/proc/rustify(turf/T)
+	var/turf/simulated/wall/W = T
+	if(istype(W) && !W.rusted)
+		W.rust()
+
 /obj/effect/spawner/random_spawners/wall_rusted_probably
 	name = "rusted wall probably"
 	icon_state = "rust"
-	result = list(
-	/turf/simulated/wall = 2,
-	/turf/simulated/wall/rust = 7)
+
+/obj/effect/spawner/random_spawners/wall_rusted_probably/randspawn(turf/T)
+	if(prob(75))
+		rustify(T)
+	qdel(src)
 
 /obj/effect/spawner/random_spawners/wall_rusted_maybe
 	name = "rusted wall maybe"
 	icon_state = "rust"
-	result = list(
-	/turf/simulated/wall = 7,
-	/turf/simulated/wall/rust = 1)
+
+/obj/effect/spawner/random_spawners/wall_rusted_maybe/randspawn(turf/T)
+	if(prob(25))
+		rustify(T)
+	qdel(src)
+
+/obj/effect/spawner/random_spawners/wall_rusted_always
+	name = "rusted wall always"
+	icon_state = "rust"
+
+/obj/effect/spawner/random_spawners/wall_rusted_always/randspawn(turf/T)
+	rustify(T)
+	qdel(src)
 
 /obj/effect/spawner/random_spawners/cobweb_left_frequent
 	name = "cobweb left frequent"