Add InventoryView#getInventory API

By: md_5 <git@md-5.net>

paper-api/src/main/java/org/bukkit/event/inventory/InventoryClickEvent.java

@@ -157,6 +157,16 @@ public class InventoryClickEvent extends InventoryInteractEvent {
         }
     }
 
+    /**
+     * Gets the inventory corresponding to the clicked slot.
+     *
+     * @see InventoryView#getInventory(int)
+     * @return inventory, or null if clicked outside
+     */
+    public Inventory getClickedInventory() {
+        return getView().getInventory(rawSlot);
+    }
+
     /**
      * The slot number that was clicked, ready for passing to
      * {@link Inventory#getItem(int)}. Note that there may be two slots with