Stack items have a number indicating stack size in inventory (#94705)

## About The Pull Request

<img width="528" height="200" alt="image"
src="https://github.com/user-attachments/assets/41a30b57-2799-44c8-82cd-ce2f8c8c22c4"
/>

Number only shows up when it's in the inventory or held - in world it
looks as-normal

(I'm pretty sure this idea was subconsciously inspired by another
server, but I don't remember...)

## Why It's Good For The Game

Makes it easier to use stacks that don't have a visual sprite change -
IE you no longer have to spam examine to see how many you have left

## Changelog

🆑 Melbert
qol: Stack items have a number indicating stack size while held or in
inventory.
/🆑

code/game/objects/items/stacks/stack.dm

@@ -125,10 +125,16 @@
 	mats_per_unit = null
 	return ..()
 
+/obj/item/stack/update_name(updates)
+	. = ..()
+	maptext = (ismob(loc) || loc?.atom_storage) ? MAPTEXT("<font color='white'>[amount]</font>") : ""
+
 /obj/item/stack/Moved(atom/old_loc, movement_dir, forced, list/old_locs, momentum_change)
 	. = ..()
 	if((!throwing || throwing.target_turf == loc) && old_loc != loc && (flags_1 & INITIALIZED_1))
 		merge_with_loc(merge_into_ourselves = !isnull(pulledby))
+	if(ismob(loc) || ismob(old_loc) || loc?.atom_storage || old_loc?.atom_storage)
+		update_appearance(UPDATE_NAME)
 
 ///Called to lazily update the materials of the item whenever the used or if more is added
 /obj/item/stack/proc/update_custom_materials()