Add Enchantment#isTreasure()Z

Determines if the enchantment is a treasure enchantment - only available via means other than the enchantment table.

src/main/java/org/bukkit/enchantments/Enchantment.java

@@ -194,6 +194,16 @@ public abstract class Enchantment {
      */
     public abstract EnchantmentTarget getItemTarget();
 
+    /**
+     * Checks if this enchantment is a treasure enchantment.
+     * <br>
+     * Treasure enchantments can only be received via looting, trading, or
+     * fishing.
+     *
+     * @return true if the enchantment is a treasure enchantment
+     */
+    public abstract boolean isTreasure();
+
     /**
      * Check if this enchantment conflicts with another enchantment.
      *

src/main/java/org/bukkit/enchantments/EnchantmentWrapper.java

@@ -44,6 +44,11 @@ public class EnchantmentWrapper extends Enchantment {
         return getEnchantment().getName();
     }
 
+    @Override
+    public boolean isTreasure() {
+        return getEnchantment().isTreasure();
+    }
+
     @Override
     public boolean conflictsWith(Enchantment other) {
         return getEnchantment().conflictsWith(other);