Adds co-op cigarette lighting (#2686)

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## About The Pull Request

If you have a cigarette equipped, and someone else has an un-lit
cigarette equipped, you can light theirs via help intent+target mouth


![image](https://github.com/shiptest-ss13/Shiptest/assets/24857008/c1a352a4-5ae5-41e3-91c7-37780cbb8535)

## Why It's Good For The Game

New co-op interaction

## Changelog

:cl:
add: If you are smoking a cigarette, you can light someone else's
cigarette via help intent while targeting the mouth
/:cl:

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

@@ -391,6 +391,14 @@
 	if(M == src && check_self_for_injuries())
 		return
 
+	if(M.zone_selected == BODY_ZONE_PRECISE_MOUTH)
+		var/obj/item/clothing/mask/cigarette/theircig = wear_mask
+		var/obj/item/clothing/mask/cigarette/ourcig = M.wear_mask
+		if(istype(ourcig) && istype(theircig))
+			if(ourcig.lit && !theircig.lit)
+				theircig.light(span_notice("[M] leans towards [src], lighting [p_their()] [theircig.name] with [M.p_their()] own."))
+				return
+
 	if(body_position == LYING_DOWN)
 		if(buckled)
 			to_chat(M, "<span class='warning'>You need to unbuckle [src] first to do that!</span>")