Fixes some sheet snatcher material bugs (#22280)

This fixes dumping the contents of the sheet snatcher would make the mat
stacks look like they only had 1 item. It also fixes so picking up
material/steel will merge with material/steel/full. And fixes that the
quick pickup method did not merge item stacks.

code/game/objects/items/weapons/storage/bags.dm

@@ -162,6 +162,19 @@
 		return 0
 	return 1
 
+// This is pretty much a copy of it, but sends it to handle_item_insertion instead.
+/obj/item/storage/bag/sheetsnatcher/handle_item_insertion_deferred(obj/item/W, mob/user)
+	if (!istype(W))
+		return FALSE
+
+	if (user)
+		user.prepare_for_slotmove(W)
+
+	if (user)
+		W.dropped(user)
+
+	handle_item_insertion(W)
+
 
 // Modified handle_item_insertion.  Would prefer not to, but...
 /obj/item/storage/bag/sheetsnatcher/handle_item_insertion(obj/item/W as obj, prevent_warning = 0)
@@ -179,7 +192,7 @@
 		amount = S.amount
 
 	for(var/obj/item/stack/material/sheet in contents)
-		if(S.type == sheet.type) // we are violating the amount limitation because these are not sane objects
+		if(S.material == sheet.material) // we are violating the amount limitation because these are not sane objects
 			sheet.amount += amount	// they should only be removed through procs in this file, which split them up.
 			S.amount -= amount
 			inserted = 1
@@ -236,6 +249,7 @@
 			var/stacksize = min(S.amount,N.max_amount)
 			N.amount = stacksize
 			S.amount -= stacksize
+			N.update_icon()
 		if(!S.amount)
 			qdel(S) // todo: there's probably something missing here
 	orient2hud(usr)