Fix backpack sprayers (#4161)

# About the pull request
fixes: #3369
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# Explain why it's good for the game
# Testing Photographs and Procedure
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# Changelog
:cl:
fix: spraying with the hose will no cost 5u of water while spaying 5u of
water.
fix: fixed the verb to take out the hose.
fix: remove the option to change the output as it was confusing for
people.
/:cl:

---------

Co-authored-by: Julien <[email protected]>

code/game/objects/items/backpack_sprayers.dm

@@ -8,6 +8,7 @@
 	w_class = SIZE_LARGE
 	flags_equip_slot = SLOT_BACK
 	flags_atom = OPENCONTAINER
+	possible_transfer_amounts = null//no point giving it possibility when mister can't it just confuse people
 	volume = 500
 	var/fill_reagent = "water"
 	var/spawn_empty = FALSE
@@ -83,8 +84,10 @@
 /obj/item/reagent_container/glass/watertank/verb/toggle_mister_verb()
 	set name = "Toggle Mister"
 	set category = "Object"
+	set src in usr
 	toggle_mister(usr)
 
+
 /obj/item/reagent_container/glass/watertank/MouseDrop(obj/over_object as obj)
 	if(!CAN_PICKUP(usr, src))
 		return ..()
@@ -132,7 +135,7 @@
 	item_state = "nozzle"
 	w_class = SIZE_LARGE
 	flags_equip_slot = null
-	amount_per_transfer_from_this = 50
+	amount_per_transfer_from_this = 5
 	possible_transfer_amounts = null
 	spray_size = 5
 	volume = 500