[Bleeding] Event no longer implements Serializable.

src/main/java/org/bukkit/event/player/PlayerItemHeldEvent.java

@@ -6,7 +6,6 @@ import org.bukkit.event.HandlerList;
 /**
  * Fired when a player changes their currently held item
  */
-@SuppressWarnings("serial")
 public class PlayerItemHeldEvent extends PlayerEvent {
     private static final HandlerList handlers = new HandlerList();
     private final int previous;