Fixes Multitool Buffer Clearing and Adds Multitool Linking Balloon Alerts (#78309)

## About The Pull Request
I was working on a feature that required the buffer of a multitool to be
cleared out after linking two devices, when I noticed it wasn't possible
to clear the multitool's buffer. The change to multitools in #77639 made
it impossible to set the buffer of a multitool to null without
destroying the stored object, yet many objects still tried to have the
multitool clear it's buffer after a successful linkage. This creates a
new proc, clear_buffer() dedicated just to clearing the buffer of a
multitool.

Also made all of the multitool linkage messages balloon alerts.

If there's any issues or things I can improve please let me know, I'm a
bit new to BYOND and DM but I'm working on learning so I can make some
more ambitious projects! _(I think I got the signaling right)_
## Why It's Good For The Game
Some objects aren't meant to be saved in the multitool's buffer after
the initial linking, this should fix that.
Also balloon alerts are nice.
## Changelog
🆑
fix: Nanotrasen has finally recalled their faulty multitools and
replaced them with working ones! The multitool's buffer now properly
clears itself.
qol: Moved multitool link messages to balloon alerts
/🆑

---------

Co-authored-by: Ghom <42542238+Ghommie@users.noreply.github.com>

code/game/machinery/botlaunchpad.dm

@@ -27,7 +27,7 @@
 		return
 	var/obj/item/multitool/multitool = tool
 	multitool.set_buffer(src)
-	to_chat(user, span_notice("You save the data in the [multitool.name]'s buffer."))
+	balloon_alert(user, "saved to multitool buffer")
 	return TOOL_ACT_TOOLTYPE_SUCCESS
 
 

code/game/machinery/launch_pad.dm

@@ -78,7 +78,7 @@
 					return
 				var/obj/item/multitool/M = I
 				M.set_buffer(src)
-				to_chat(user, span_notice("You save the data in the [I.name]'s buffer."))
+				balloon_alert(user, "saved to multitool buffer")
 				return 1
 
 		if(default_deconstruction_crowbar(I))

code/game/machinery/mechlaunchpad.dm

@@ -37,7 +37,7 @@
 		return
 	var/obj/item/multitool/multitool = tool
 	multitool.set_buffer(src)
-	to_chat(user, span_notice("You save the data in the [multitool.name]'s buffer."))
+	balloon_alert(user, "saved to multitool buffer")
 	return TRUE
 
 /obj/machinery/mechpad/wirecutter_act(mob/living/user, obj/item/tool)

code/game/machinery/porta_turret/portable_turret.dm

@@ -351,7 +351,7 @@ DEFINE_BITFIELD(turret_flags, list(
 			return
 		var/obj/item/multitool/M = I
 		M.set_buffer(src)
-		to_chat(user, span_notice("You add [src] to multitool buffer."))
+		balloon_alert(user, "saved to multitool buffer")
 	else
 		return ..()
 

code/game/machinery/porta_turret/portable_turret_cover.dm

@@ -66,7 +66,7 @@
 			return
 		var/obj/item/multitool/M = I
 		M.set_buffer(parent_turret)
-		to_chat(user, span_notice("You add [parent_turret] to multitool buffer."))
+		balloon_alert(user, "saved to multitool buffer")
 		return
 	return ..()
 

code/game/machinery/quantum_pad.dm

@@ -63,6 +63,7 @@
 				return
 			var/obj/item/multitool/M = I
 			M.set_buffer(src)
+			balloon_alert(user, "saved to multitool buffer")
 			to_chat(user, span_notice("You save the data in [I]'s buffer. It can now be saved to pads with closed panels."))
 			return TRUE
 	else if(I.tool_behaviour == TOOL_MULTITOOL)
@@ -71,14 +72,14 @@
 		var/obj/item/multitool/M = I
 		if(istype(M.buffer, /obj/machinery/quantumpad))
 			if(M.buffer == src)
-				to_chat(user, span_warning("You cannot link a pad to itself!"))
+				balloon_alert(user, "cannot link to self!")
 				return TRUE
 			else
 				linked_pad = M.buffer
-				to_chat(user, span_notice("You link [src] to the one in [I]'s buffer."))
+				balloon_alert(user, "data uploaded from buffer")
 				return TRUE
 		else
-			to_chat(user, span_warning("There is no quantum pad data saved in [I]'s buffer!"))
+			balloon_alert(user, "no quantum pad data found!")
 			return TRUE
 
 	else if(istype(I, /obj/item/quantum_keycard))

code/game/machinery/teleporter.dm

@@ -166,13 +166,13 @@
 		var/obj/item/multitool/M = W
 		if(panel_open)
 			M.set_buffer(src)
-			to_chat(user, span_notice("You download the data to the [W.name]'s buffer."))
+			balloon_alert(user, "saved to multitool buffer")
 		else
 			if(M.buffer && istype(M.buffer, /obj/machinery/teleport/station) && M.buffer != src)
 				if(linked_stations.len < efficiency)
 					linked_stations.Add(M.buffer)
 					M.set_buffer(null)
-					to_chat(user, span_notice("You upload the data from the [W.name]'s buffer."))
+					balloon_alert(user, "data uploaded from buffer")
 				else
 					to_chat(user, span_alert("This station can't hold more information, try to use better parts."))
 		return

code/game/objects/items/devices/multitool.dm

@@ -41,14 +41,25 @@
 	user.visible_message(span_suicide("[user] puts the [src] to [user.p_their()] chest. It looks like [user.p_theyre()] trying to pulse [user.p_their()] heart off!"))
 	return OXYLOSS//theres a reason it wasn't recommended by doctors
 
+/**
+ * Sets the multitool internal object buffer
+ *
+ * Arguments:
+ * * buffer - the new object to assign to the multitool's buffer
+ */
 /obj/item/multitool/proc/set_buffer(datum/buffer)
 	if(src.buffer)
 		UnregisterSignal(src.buffer, COMSIG_QDELETING)
-	if(QDELETED(buffer))
-		return
 	src.buffer = buffer
-	RegisterSignal(buffer, COMSIG_QDELETING, PROC_REF(on_buffer_del))
+	if(!QDELETED(buffer))
+		RegisterSignal(buffer, COMSIG_QDELETING, PROC_REF(on_buffer_del))
 
+/**
+ * Called when the buffer's stored object is deleted
+ *
+ * This proc does not clear the buffer of the multitool, it is here to
+ * handle the deletion of the object the buffer references
+ */
 /obj/item/multitool/proc/on_buffer_del(datum/source)
 	SIGNAL_HANDLER
 	buffer = null

code/modules/antagonists/pirate/pirate_shuttle_equipment.dm

@@ -183,8 +183,8 @@
 /obj/machinery/piratepad/multitool_act(mob/living/user, obj/item/multitool/I)
 	. = ..()
 	if (istype(I))
-		to_chat(user, span_notice("You register [src] in [I]s buffer."))
 		I.set_buffer(src)
+		balloon_alert(user, "saved to multitool buffer")
 		return TRUE
 
 /obj/machinery/piratepad/screwdriver_act_secondary(mob/living/user, obj/item/screwdriver/screw)

code/modules/atmospherics/machinery/components/unary_devices/bluespace_sender.dm

@@ -123,7 +123,7 @@ GLOBAL_LIST_EMPTY_TYPED(bluespace_senders, /obj/machinery/atmospherics/component
 /obj/machinery/atmospherics/components/unary/bluespace_sender/multitool_act(mob/living/user, obj/item/item)
 	var/obj/item/multitool/multitool = item
 	multitool.set_buffer(src)
-	to_chat(user, span_notice("You store linkage information in [item]'s buffer."))
+	balloon_alert(user, "saved to multitool buffer")
 	return TRUE
 
 /obj/machinery/atmospherics/components/unary/bluespace_sender/wrench_act(mob/living/user, obj/item/tool)

code/modules/food_and_drinks/machinery/monkeyrecycler.dm

@@ -98,6 +98,6 @@ GLOBAL_LIST_EMPTY(monkey_recyclers)
 /obj/machinery/monkey_recycler/multitool_act(mob/living/user, obj/item/multitool/I)
 	. = ..()
 	if(istype(I))
-		to_chat(user, span_notice("You log [src] in the multitool's buffer."))
 		I.set_buffer(src)
+		balloon_alert(user, "saved to multitool buffer")
 		return TRUE

code/modules/mining/machine_silo.dm

@@ -165,8 +165,8 @@ GLOBAL_LIST_EMPTY(silo_access_logs)
 /obj/machinery/ore_silo/multitool_act(mob/living/user, obj/item/multitool/I)
 	. = ..()
 	if (istype(I))
-		to_chat(user, span_notice("You log [src] in the multitool's buffer."))
 		I.set_buffer(src)
+		balloon_alert(user, "saved to multitool buffer")
 		return TRUE
 
 /**

code/modules/mining/machine_stacking.dm

@@ -27,7 +27,7 @@
 		return
 	var/obj/item/multitool/M = I
 	M.set_buffer(src)
-	to_chat(user, span_notice("You store linkage information in [I]'s buffer."))
+	balloon_alert(user, "saved to multitool buffer")
 	return TRUE
 
 /obj/machinery/mineral/stacking_unit_console/ui_interact(mob/user, datum/tgui/ui)

code/modules/paperwork/ticketmachine.dm

@@ -56,7 +56,7 @@ MAPPING_DIRECTIONAL_HELPERS(/obj/machinery/ticket_machine, 32)
 		return
 	var/obj/item/multitool/M = I
 	M.set_buffer(src)
-	to_chat(user, span_notice("You store linkage information in [I]'s buffer."))
+	balloon_alert(user, "saved to multitool buffer")
 	return TRUE
 
 /obj/machinery/ticket_machine/emag_act(mob/user, obj/item/card/emag/emag_card) //Emag the ticket machine to dispense burning tickets, as well as randomize its number to destroy the HoP's mind.

code/modules/plumbing/plumbers/teleporter.dm

@@ -73,7 +73,7 @@
 
 	var/obj/item/multitool/M = I
 	M.set_buffer(src)
-	to_chat(user, span_notice("You store linkage information in [I]'s buffer."))
+	balloon_alert(user, "saved to multitool buffer")
 	return TRUE
 
 /obj/machinery/plumbing/receiver/process(seconds_per_tick)

code/modules/research/server.dm

@@ -109,7 +109,7 @@
 	if(!stored_research)
 		return
 	tool.set_buffer(stored_research)
-	to_chat(user, span_notice("Stored [src]'s techweb information in [tool]."))
+	balloon_alert(user, "saved to multitool buffer")
 	return TRUE
 
 /// Master R&D server. As long as this still exists and still holds the HDD for the theft objective, research points generate at normal speed. Destroy it or an antag steals the HDD? Half research speed.

code/modules/station_goals/bsa.dm

@@ -55,7 +55,7 @@ GLOBAL_VAR_INIT(bsa_unlock, FALSE)
 		return
 	var/obj/item/multitool/M = I
 	M.set_buffer(src)
-	to_chat(user, span_notice("You store linkage information in [I]'s buffer."))
+	balloon_alert(user, "saved to multitool buffer")
 	return TRUE
 
 /obj/machinery/bsa/front
@@ -72,7 +72,7 @@ GLOBAL_VAR_INIT(bsa_unlock, FALSE)
 		return
 	var/obj/item/multitool/M = I
 	M.set_buffer(src)
-	to_chat(user, span_notice("You store linkage information in [I]'s buffer."))
+	balloon_alert(user, "saved to multitool buffer")
 	return TRUE
 
 /obj/machinery/bsa/middle