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

* Replaced body zone magic strings with defines

* merge conflicts

code/game/objects/items/defib.dm

@@ -417,7 +417,7 @@
 	var/mob/living/carbon/H = M
 
 
-	if(user.zone_selected != "chest")
+	if(user.zone_selected != BODY_ZONE_CHEST)
 		to_chat(user, "<span class='warning'>You need to target your patient's chest with [src]!</span>")
 		return
 
@@ -507,7 +507,7 @@
 					H.visible_message("<span class='warning'>[H] thrashes wildly, clutching at their chest!</span>",
 						"<span class='userdanger'>You feel a horrible agony in your chest!</span>")
 				H.set_heartattack(TRUE)
-			H.apply_damage(50, BURN, "chest")
+			H.apply_damage(50, BURN, BODY_ZONE_CHEST)
 			add_logs(user, H, "overloaded the heart of", defib)
 			H.Knockdown(100)
 			H.Jitter(100)
@@ -626,7 +626,7 @@
 	icon_state = "defibpaddles0"
 	item_state = "defibpaddles0"
 	req_defib = FALSE
-	
+
 /obj/item/twohanded/shockpaddles/cyborg/attack(mob/M, mob/user)
 	if(iscyborg(user))
 		var/mob/living/silicon/robot/R = user