Code Generation for TypedKeys (#9233)

Currently includes generated key holder classes for types
used in the Registry Modification API

patches/api/0201-Improve-Arrow-API.patch

@@ -0,0 +1,43 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Nesaak <52047222+Nesaak@users.noreply.github.com>
+Date: Fri, 22 May 2020 13:35:21 -0400
+Subject: [PATCH] Improve Arrow API
+
+Add method to get the arrow's itemstack and a method
+to set the arrow's "noclip" status
+
+Co-authored-by: Jake Potrebic <jake.m.potrebic@gmail.com>
+
+diff --git a/src/main/java/org/bukkit/entity/AbstractArrow.java b/src/main/java/org/bukkit/entity/AbstractArrow.java
+index e8e56e89e32d84af0639fe2e9b0eeabd747b6007..225a24898acd25038ea2a8448f9f3b57643d3026 100644
+--- a/src/main/java/org/bukkit/entity/AbstractArrow.java
++++ b/src/main/java/org/bukkit/entity/AbstractArrow.java
+@@ -143,6 +143,28 @@ public interface AbstractArrow extends Projectile {
+     }
+ 
+     // Paper start
++    /**
++     * Gets the ItemStack for this arrow.
++     *
++     * @return The ItemStack, as if a player picked up the arrow
++     */
++    @NotNull
++    org.bukkit.inventory.ItemStack getItemStack();
++
++    /**
++     * Sets this arrow to "noclip" status.
++     *
++     * @param noPhysics true to set "noclip"
++     */
++    void setNoPhysics(boolean noPhysics);
++
++    /**
++     * Gets if this arrow has "noclip".
++     *
++     * @return true if noclip is active
++     */
++    boolean hasNoPhysics();
++
+     /**
+      * Gets the {@link PickupRule} for this arrow.
+      *