New chat events for better Adventure support (#5289)

Bump Adventure to 4.6.0

fixes #5216
fixes #5261
fixes #5287

Spigot-API-Patches/0259-Add-sendOpLevel-API.patch

@@ -0,0 +1,28 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Mariell Hoversholm <proximyst@proximyst.com>
+Date: Tue, 29 Dec 2020 15:02:57 +0100
+Subject: [PATCH] Add sendOpLevel API
+
+
+diff --git a/src/main/java/org/bukkit/entity/Player.java b/src/main/java/org/bukkit/entity/Player.java
+index 46eb684a23b1b8321a91f1e70b8196706aebd9bc..5fe48dcc5a3ea492915350cff44d5f112ce11dbf 100644
+--- a/src/main/java/org/bukkit/entity/Player.java
++++ b/src/main/java/org/bukkit/entity/Player.java
+@@ -1963,6 +1963,17 @@ public interface Player extends HumanEntity, Conversable, OfflinePlayer, PluginM
+      */
+     @Nullable
+     Firework boostElytra(@NotNull ItemStack firework);
++
++    /**
++     * Send a packet to the player indicating its operator status level.
++     * <p>
++     * <b>Note:</b> This will not persist across more than the current connection, and setting the player's operator
++     * status as a later point <i>will</i> override the effects of this.
++     *
++     * @param level The level to send to the player. Must be in {@code [0, 4]}.
++     * @throws IllegalArgumentException If the level is negative or greater than {@code 4} (i.e. not within {@code [0, 4]}).
++     */
++    void sendOpLevel(byte level);
+     // Paper end
+ 
+     // Spigot start