refactors washing items

fixes #3570
Could have fixed with another if statement in sink/attackby, but it was
already pretty snowflakey, and had the potential to get worse
Items now have a wash proc that the sink calls, that can be overridden
when needed

code/modules/reagents/reagent_containers.dm

@@ -71,4 +71,11 @@
 		for (var/datum/reagent/R in snack.reagents.reagent_list) //no reagents will be left behind
 			data += "[R.id]([R.volume] units); " //Using IDs because SOME chemicals(I'm looking at you, chlorhydrate-beer) have the same names as other chemicals.
 		return data
-	else return "No reagents"
+	else return "No reagents"
+
+/obj/item/weapon/reagent_containers/wash(mob/user, atom/source)
+	if(is_open_container())
+		reagents.add_reagent("water", min(volume - reagents.total_volume, amount_per_transfer_from_this))
+		user << "<span class='notice'>You fill [src] from [source].</span>"
+		return
+	..()

code/modules/reagents/reagent_containers/food/snacks.dm

@@ -1674,6 +1674,13 @@
 	if(volume >= 5)
 		return Expand()
 
+/obj/item/weapon/reagent_containers/food/snacks/monkeycube/wash(mob/user, atom/source)
+	if(wrapped)
+		..()
+		return
+	if(do_after(user, 40, target = source))
+		return 1
+
 /obj/item/weapon/reagent_containers/food/snacks/monkeycube/proc/Expand()
 	if(isnull(gcDestroyed))
 		visible_message("<span class='notice'>[src] expands!</span>")