Several fixes and new api for experience merging/stacking (#9242)

patches/server/0811-Win-Screen-API.patch

@@ -0,0 +1,38 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Lama06 <andreasprues36@gmail.com>
+Date: Sat, 21 Jan 2023 13:53:23 +0100
+Subject: [PATCH] Win Screen API
+
+== AT ==
+public net.minecraft.server.level.ServerPlayer seenCredits
+
+diff --git a/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java b/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
+index 9716687ba5aa407d714389c50b00e8c7ecf88724..79ab080e496df2b8d11c777427863bd775e60b91 100644
+--- a/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
++++ b/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
+@@ -1292,6 +1292,25 @@ public class CraftPlayer extends CraftHumanEntity implements Player {
+         this.getHandle().connection.send(packet);
+     }
+ 
++    // Paper start
++    @Override
++    public void showWinScreen() {
++        if (getHandle().connection == null) return;
++        var packet = new ClientboundGameEventPacket(ClientboundGameEventPacket.WIN_GAME, 1);
++        getHandle().connection.send(packet);
++    }
++
++    @Override
++    public boolean hasSeenWinScreen() {
++        return getHandle().seenCredits;
++    }
++
++    @Override
++    public void setHasSeenWinScreen(boolean hasSeenWinScreen) {
++        getHandle().seenCredits = hasSeenWinScreen;
++    }
++    // Paper end
++
+     @Override
+     public void setRotation(float yaw, float pitch) {
+         // Paper start - Teleport API