[MIRROR] Replaced body zone magic strings with defines (#6004)

* Replaced body zone magic strings with defines

* merge conflicts

code/modules/zombie/items.dm

@@ -54,7 +54,7 @@
 	user.visible_message("<span class='suicide'>[user] is ripping [user.p_their()] brains out! It looks like [user.p_theyre()] trying to commit suicide!</span>")
 	if(isliving(user))
 		var/mob/living/L = user
-		var/obj/item/bodypart/O = L.get_bodypart("head")
+		var/obj/item/bodypart/O = L.get_bodypart(BODY_ZONE_HEAD)
 		if(O)
 			O.dismember()
 	return (BRUTELOSS)

code/modules/zombie/organs.dm

@@ -1,7 +1,7 @@
 /obj/item/organ/zombie_infection
 	name = "festering ooze"
 	desc = "A black web of pus and viscera."
-	zone = "head"
+	zone = BODY_ZONE_HEAD
 	slot = ORGAN_SLOT_ZOMBIE
 	icon_state = "blacktumor"
 	var/datum/species/old_species = /datum/species/human