SPIGOT-5887: ClickType doesn't include off hand swaps

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

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

@@ -53,6 +53,10 @@ public enum ClickType {
      * Any action done with the Creative inventory open.
      */
     CREATIVE,
+    /**
+     * The "swap item with offhand" key (defaults to F).
+     */
+    SWAP_OFFHAND,
     /**
      * A type of inventory manipulation not yet recognized by Bukkit.
      * <p>

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

@@ -68,10 +68,14 @@ public enum InventoryAction {
     /**
      * The clicked item is moved to the hotbar, and the item currently there
      * is re-added to the player's inventory.
+     *
+     * The hotbar includes the player's off hand.
      */
     HOTBAR_MOVE_AND_READD,
     /**
      * The clicked slot and the picked hotbar slot are swapped.
+     *
+     * The hotbar includes the player's off hand.
      */
     HOTBAR_SWAP,
     /**