Add disk numbers 1 through 4 (currently roman numerals)

disk.gd

@@ -2,6 +2,9 @@ extends Pickup
 
 @export var disk_num: int
 
+func _ready() -> void:
+	$DiskNumber.texture = load("res://art/numbers/%d.png" % disk_num)
+
 func _on_picked_up() -> void:
 	%Player2D.give_disk(disk_num)
 	%Player2D.give_objective("disk%d" % disk_num, "Install data disk %d" % disk_num)