Remove custom equals/hashCode from ReferencingInventory.PlayerStorageContents

This partially reverts 0e581fb. The problem with this is that it doesn't consider other parts of the inventory, e.g. event handlers. Additionally, equals/hashCode cannot be properly implemented for ReferencingInventory due to its usage of functional interfaces.
The impact of this change should be small. Users can get back to the previous slot-deduplicating behavior by simply using the same ReferencingInventory.PlayerStorageContents instance for all affected slots.

Author: NichtStudioCode

invui/src/main/java/xyz/xenondevs/invui/inventory/ReferencingInventory.java

@@ -18,8 +18,6 @@
 import java.util.function.BiFunction;
 import java.util.function.Function;
 
-// TODO: equals+hashCode for normal referencing inventories
-
 /**
  * A {@link xyz.xenondevs.invui.inventory.Inventory} which is backed by a bukkit {@link Inventory}.
  * <p>
@@ -245,16 +243,6 @@ public PlayerInventory getReferencedInventory() {
             return (PlayerInventory) super.getReferencedInventory();
         }
 
-        @Override
-        public int hashCode() {
-            return getReferencedInventory().hashCode();
-        }
-        
-        @Override
-        public boolean equals(Object obj) {
-            return obj instanceof ReferencingInventory.PlayerStorageContents other &&
-                   getReferencedInventory().equals(other.getReferencedInventory());
-        }
     }
 
 }