Burning paper (and similar) is now two way (you can hold a paper to your cigarette to burn it) (#90307)

## About The Pull Request

1. Burning paper (and similar) is now two way - rather than
necessitating you touch the paper with the burning thing, you can now
touch the burning thing with the paper

2. You can now light a cigarette on a lit candle

3. Candles no longer craft into flashlight eyes

## Why It's Good For The Game

1. Burning money with a cigarette larp 

2. Cool Frenchman larp

3. ??? I noticed you can't light a candle with a candle because it tried
to craft flashlight eyes.

## Changelog

🆑 Melbert
qol: Burning paper (and similar) is now two way. Rather than needing to
click on the paper with a burning item, you can now click on a burning
item with the paper. This means you can burn paper on your lit cigarette
like a badass.
qol: You can now light cigarettes on candles. 
del: Flares and candles can no longer craft into flashlight eyes, I
guess.
/🆑

code/modules/paperwork/folders.dm

@@ -27,6 +27,7 @@
 /obj/item/folder/Initialize(mapload)
 	update_icon()
 	. = ..()
+	AddElement(/datum/element/burn_on_item_ignition)
 
 /obj/item/folder/Destroy()
 	for(var/obj/important_thing in contents)
@@ -79,8 +80,6 @@
 	return paper_overlay
 
 /obj/item/folder/attackby(obj/item/weapon, mob/user, params)
-	if(burn_paper_product_attackby_check(weapon, user))
-		return
 	if(is_type_in_typecache(weapon, folder_insertables))
 		//Add paper, photo or documents into the folder
 		if(!user.transferItemToLoc(weapon, src))

code/modules/paperwork/paper.dm

@@ -79,6 +79,9 @@
 	if(can_become_message_in_bottle && !mapload && prob(MESSAGE_BOTTLE_CHANCE))
 		LAZYADD(SSpersistence.queued_message_bottles, src)
 
+	AddElement(/datum/element/burn_on_item_ignition)
+	RegisterSignal(src, COMSIG_ATOM_IGNITED_BY_ITEM, PROC_REF(close_paper_ui))
+
 /obj/item/paper/Destroy()
 	camera_holder = null
 	clear_paper()
@@ -90,6 +93,10 @@
 		custom_fire_overlay = mutable_appearance('icons/obj/service/bureaucracy.dmi', "paper_onfire_overlay", appearance_flags = RESET_COLOR|KEEP_APART)
 	return custom_fire_overlay
 
+/obj/item/paper/proc/close_paper_ui()
+	SIGNAL_HANDLER
+	SStgui.close_uis(src)
+
 /// Determines whether this paper has been written or stamped to.
 /obj/item/paper/proc/is_empty()
 	return !(LAZYLEN(raw_text_inputs) || LAZYLEN(raw_stamp_data))
@@ -407,37 +414,7 @@
 		user.put_in_hands(new_plane)
 	return new_plane
 
-/obj/item/proc/burn_paper_product_attackby_check(obj/item/attacking_item, mob/living/user, bypass_clumsy = FALSE)
-	//can't be put on fire!
-	if((resistance_flags & FIRE_PROOF) || !(resistance_flags & FLAMMABLE))
-		return FALSE
-	//already on fire!
-	if(resistance_flags & ON_FIRE)
-		return FALSE
-	var/ignition_message = attacking_item.ignition_effect(src, user)
-	if(!ignition_message)
-		return FALSE
-	if(!bypass_clumsy && HAS_TRAIT(user, TRAIT_CLUMSY) && prob(10) && Adjacent(user))
-		user.visible_message(span_warning("[user] accidentally ignites [user.p_them()]self!"), \
-							span_userdanger("You miss [src] and accidentally light yourself on fire!"))
-		if(user.is_holding(attacking_item)) //checking if they're holding it in case TK is involved
-			user.dropItemToGround(attacking_item)
-		user.adjust_fire_stacks(attacking_item)
-		user.ignite_mob()
-		return TRUE
-
-	if(user.is_holding(src)) //no TK shit here.
-		user.dropItemToGround(src)
-	user.visible_message(ignition_message)
-	add_fingerprint(user)
-	fire_act(attacking_item.get_temperature())
-	return TRUE
-
 /obj/item/paper/attackby(obj/item/attacking_item, mob/living/user, params)
-	if(burn_paper_product_attackby_check(attacking_item, user))
-		SStgui.close_uis(src)
-		return
-
 	// Enable picking paper up by clicking on it with the clipboard or folder
 	if(istype(attacking_item, /obj/item/clipboard) || istype(attacking_item, /obj/item/folder) || istype(attacking_item, /obj/item/paper_bin))
 		attacking_item.attackby(src, user)
@@ -530,6 +507,8 @@
 	)
 
 /obj/item/paper/ui_interact(mob/user, datum/tgui/ui)
+	if(resistance_flags & ON_FIRE)
+		return
 	ui = SStgui.try_update_ui(user, src, ui)
 	if(!ui)
 		ui = new(user, src, "PaperSheet", name)

code/modules/paperwork/paperplane.dm

@@ -35,6 +35,7 @@
 	if(istype(internal_paper, /obj/item/paper/carbon_copy))
 		icon_state = "[base_icon_state]_carbon"
 	update_appearance(UPDATE_ICON)
+	AddElement(/datum/element/burn_on_item_ignition)
 
 /obj/item/paperplane/Exited(atom/movable/gone, direction)
 	. = ..()
@@ -80,8 +81,6 @@
 	user.put_in_hands(released_paper)
 
 /obj/item/paperplane/attackby(obj/item/attacking_item, mob/user, params)
-	if(burn_paper_product_attackby_check(attacking_item, user))
-		return
 	if(IS_WRITING_UTENSIL(attacking_item))
 		to_chat(user, span_warning("You should unfold [src] before changing it!"))
 		return

code/modules/paperwork/ticketmachine.dm

@@ -253,6 +253,7 @@ MAPPING_DIRECTIONAL_HELPERS(/obj/machinery/ticket_machine, 32)
 		name += " #[num]"
 		saved_maptext = MAPTEXT(num)
 		maptext = saved_maptext
+	AddElement(/datum/element/burn_on_item_ignition)
 
 /obj/item/ticket_machine_ticket/examine(mob/user)
 	. = ..()
@@ -265,12 +266,6 @@ MAPPING_DIRECTIONAL_HELPERS(/obj/machinery/ticket_machine, 32)
 	. = ..()
 	maptext = saved_maptext //For some reason, storage code removes all maptext off objs, this stops its number from being wiped off when taken out of storage.
 
-/obj/item/ticket_machine_ticket/attackby(obj/item/P, mob/living/carbon/human/user, params) //Stolen from papercode
-	if(burn_paper_product_attackby_check(P, user))
-		return
-
-	return ..()
-
 /obj/item/ticket_machine_ticket/Destroy()
 	if(source)
 		source.ticket_holders -= owner_ref