SPIGOT-1576: Add more new 1.9 enchants.

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

paper-api/src/main/java/org/bukkit/enchantments/Enchantment.java

@@ -55,6 +55,11 @@ public abstract class Enchantment {
      */
     public static final Enchantment DEPTH_STRIDER = new EnchantmentWrapper(8);
 
+    /**
+     * Freezes any still water adjacent to ice / frost which player is walking on
+     */
+    public static final Enchantment FROST_WALKER = new EnchantmentWrapper(9);
+
     /**
      * Increases damage against all targets
      */
@@ -136,6 +141,11 @@ public abstract class Enchantment {
      */
     public static final Enchantment LURE = new EnchantmentWrapper(62);
 
+    /**
+     * Allows mending the item using experience orbs
+     */
+    public static final Enchantment MENDING = new EnchantmentWrapper(70);
+
     private static final Map<Integer, Enchantment> byId = new HashMap<Integer, Enchantment>();
     private static final Map<String, Enchantment> byName = new HashMap<String, Enchantment>();
     private static boolean acceptingNew = true;