Replaces HasEntered() with Crossed() and reduces redundant checks on turf/Enter()

code/modules/mob/dead/observer/observer.dm

@@ -101,7 +101,7 @@ This is the proc mobs get to turn into a ghost. Forked from ghostize due to comp
 	if(NewLoc)
 		loc = NewLoc
 		for(var/obj/effect/step_trigger/S in NewLoc)
-			S.HasEntered(src)
+			S.Crossed(src)
 
 		return
 	loc = get_turf(src) //Get out of closets and such as a ghost
@@ -115,7 +115,7 @@ This is the proc mobs get to turn into a ghost. Forked from ghostize due to comp
 		x--
 
 	for(var/obj/effect/step_trigger/S in locate(x, y, z))	//<-- this is dumb
-		S.HasEntered(src)
+		S.Crossed(src)
 
 /mob/dead/observer/examine()
 	if(usr)

code/modules/mob/living/carbon/alien/special/facehugger.dm

@@ -80,7 +80,7 @@ var/const/MAX_ACTIVE_TIME = 400
 /obj/item/clothing/mask/facehugger/equipped(mob/M)
 	Attach(M)
 
-/obj/item/clothing/mask/facehugger/HasEntered(atom/target)
+/obj/item/clothing/mask/facehugger/Crossed(atom/target)
 	HasProximity(target)
 	return
 

code/modules/mob/living/carbon/human/human.dm

@@ -428,7 +428,7 @@
 
 // called when something steps onto a human
 // this could be made more general, but for now just handle mulebot
-/mob/living/carbon/human/HasEntered(var/atom/movable/AM)
+/mob/living/carbon/human/Crossed(var/atom/movable/AM)
 	var/obj/machinery/bot/mulebot/MB = AM
 	if(istype(MB))
 		MB.RunOver(src)

code/modules/mob/living/simple_animal/friendly/mouse.dm

@@ -170,7 +170,7 @@
 	src << "<span class='warning'>You are too small to pull anything.</span>"
 	return
 
-/mob/living/simple_animal/mouse/HasEntered(AM as mob|obj)
+/mob/living/simple_animal/mouse/Crossed(AM as mob|obj)
 	if( ishuman(AM) )
 		if(!stat)
 			var/mob/M = AM