Use itemstack in LivingEntityUseItemEvent.Finish before it was used (#5015)

src/main/java/net/minecraftforge/event/entity/living/LivingEntityUseItemEvent.java

@@ -113,6 +113,8 @@ public class LivingEntityUseItemEvent extends LivingEvent
      * Fired after an item has fully finished being used.
      * The item has been notified that it was used, and the item/result stacks reflect after that state.
      * This means that when this is fired for a Potion, the potion effect has already been applied.
+     * 
+     * {@link LivingEntityUseItemEvent#item} is a copy of the item BEFORE it was used.
      *
      * If you wish to cancel those effects, you should cancel one of the above events.
      *