Refactored movement observable away (#20083)

Refactored movement observable away, use only the signal.
Some tweaks to the signal.

code/game/objects/items/devices/slide_projector.dm

@@ -68,7 +68,7 @@
 /obj/item/storage/slide_projector/proc/stop_projecting()
 	if(projection)
 		QDEL_NULL(projection)
-	GLOB.moved_event.unregister(src, src, PROC_REF(check_projections))
+	UnregisterSignal(src, COMSIG_MOVABLE_MOVED)
 	set_light(0)
 	update_icon()
 
@@ -83,7 +83,7 @@
 			break
 	projection = new projection_type(target)
 	projection.set_source(current_slide)
-	GLOB.moved_event.register(src, src, PROC_REF(check_projections))
+	RegisterSignal(src, COMSIG_MOVABLE_MOVED, PROC_REF(check_projections))
 	set_light(1.4, 0.1, COLOR_WHITE) //Bit of light
 	update_icon()
 

code/game/objects/items/easel.dm

@@ -9,12 +9,12 @@
 
 /obj/structure/easel/Initialize(ml, _mat, _reinf_mat)
 	. = ..()
-	GLOB.moved_event.register(src, src, PROC_REF(move_painting))
+	RegisterSignal(src, COMSIG_MOVABLE_MOVED, PROC_REF(move_painting))
 	material = SSmaterials.get_material_by_name(MATERIAL_WOOD)
 
 /obj/structure/easel/Destroy()
 	painting = null
-	GLOB.moved_event.unregister(src, src, PROC_REF(move_painting))
+	UnregisterSignal(src, COMSIG_MOVABLE_MOVED)
 	return ..()
 
 /*

code/game/objects/structures/target_stake.dm

@@ -43,8 +43,6 @@
 		T.pixel_x = 0
 		T.pixel_y = 0
 		T.layer = ABOVE_OBJ_LAYER
-		GLOB.moved_event.register(T, src, TYPE_PROC_REF(/atom/movable, move_to_turf))
-		GLOB.moved_event.register(src, T, TYPE_PROC_REF(/atom/movable, move_to_turf))
 		T.stake = src
 		pinned_target = T
 	else
@@ -52,8 +50,6 @@
 		if(pinned_target)
 			pinned_target.density = FALSE
 			pinned_target.layer = OBJ_LAYER
-			GLOB.moved_event.unregister(pinned_target, src)
-			GLOB.moved_event.unregister(src, pinned_target)
 			pinned_target.stake = null
 		pinned_target = null