Add some constants to AnimatePacket

src/pocketmine/event/player/PlayerAnimationEvent.php

@@ -32,6 +32,10 @@ use pocketmine\Player;
 class PlayerAnimationEvent extends PlayerEvent implements Cancellable{
 	public static $handlerList = null;
 
+	/**
+	 * @deprecated This is dependent on the protocol and should not be here.
+	 * Use the constants in {@link pocketmine\network\mcpe\protocol\AnimatePacket} instead.
+	 */
 	const ARM_SWING = 1;
 
 	/** @var int */