port PaperMC/Paper#12654, closes #1665

Author: granny

purpur-server/minecraft-patches/sources/net/minecraft/world/inventory/AbstractContainerMenu.java.patch

@@ -8,3 +8,12 @@
      // CraftBukkit start
      public boolean checkReachable = true;
      public abstract org.bukkit.inventory.InventoryView getBukkitView();
+@@ -552,7 +_,7 @@
+ 
+                 slot.setChanged();
+                 // CraftBukkit start - Make sure the client has the right slot contents
+-                if (player instanceof ServerPlayer serverPlayer && slot.getMaxStackSize() != 64) {
++                if (player instanceof ServerPlayer serverPlayer && slot.getMaxStackSize() != net.minecraft.world.Container.MAX_STACK) { // Purpur - PaperPR#12654
+                     serverPlayer.connection.send(new net.minecraft.network.protocol.game.ClientboundContainerSetSlotPacket(this.containerId, this.incrementStateId(), slot.index, slot.getItem()));
+                     // Updating a crafting inventory makes the client reset the result slot, have to send it again
+                     if (this.getBukkitView().getType() == org.bukkit.event.inventory.InventoryType.WORKBENCH || this.getBukkitView().getType() == org.bukkit.event.inventory.InventoryType.CRAFTING) {