One Shot RPG (shiptest-ss13#3433)

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## About The Pull Request
Adds a one-shot rocket launcher to the code. Adjusts the code in some
places to support it being truly one shot. Also adds being able to draw
on rocket launchers for mild entertainment.
Rye did the sprite.
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## Why It's Good For The Game
A disposable anti-armor tool is good for people who are poor and or
frontiersmen.
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## Changelog
Rye, Erika 
:cl:
add: One-Shot Rocket Launcher. A quick solution to an armored problem. 
add: You can now scribble profane things onto the tube of your rocket
launcher. Use this power wisely.
imageadd: Rye: A sprite for a one-shot rocket launcher
/:cl:

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code/modules/projectiles/guns/ballistic/launchers.dm

@@ -55,7 +55,7 @@ GLOBAL_LIST_INIT(rpg_scrawlings, list(
 
 /obj/item/gun/ballistic/rocketlauncher
 	name = "\improper PML-9"
-	desc = "A reusable rocket-propelled grenade launcher. The words \"NT this way\" and an arrow have been written near the barrel."
+	desc = "A reusable rocket-propelled grenade launcher."
 
 	icon_state = "rocketlauncher"
 	item_state = "rocketlauncher"
@@ -81,9 +81,28 @@ GLOBAL_LIST_INIT(rpg_scrawlings, list(
 
 	manufacturer = MANUFACTURER_SCARBOROUGH
 
+	attack_verb = list("bludgeoned", "hit", "slammed", "whacked")
+
 	valid_attachments = list()
 	slot_available = list()
 
+	var/rpg_scribble = null
+
+/obj/item/gun/ballistic/rocketlauncher/Initialize()
+	. = ..()
+	rpg_scribble = pick(GLOB.rpg_scrawlings)
+	desc += " [rpg_scribble] is scrawled on the tube"
+
+/obj/item/gun/ballistic/rocketlauncher/attackby(obj/item/A, mob/user, params)
+	. = ..()
+	if(istype(A, /obj/item/pen))
+		rpg_scribble = stripped_input(user, "What are you putting on [src]?", "Rocket Launcher Doodle")
+		if(!rpg_scribble || !length(rpg_scribble))
+			desc = "[src::desc]"
+			return
+		desc = "[src::desc] [rpg_scribble] is scribbled on the body."
+
+
 /obj/item/gun/ballistic/rocketlauncher/afterattack()
 	. = ..()
 	magazine.get_round(FALSE) //Hack to clear the mag after it's fired