Expose anvil cost in the API (#10682)

patches/api/More-Enchantment-API.patch

@@ -4,6 +4,7 @@ Date: Thu, 6 May 2021 19:58:03 -0700
 Subject: [PATCH] More Enchantment API
 
 Co-authored-by: Luis <luisc99@icloud.com>
+Co-authored-by: Janet Blackquill <uhhadd@gmail.com>
 
 diff --git a/src/main/java/io/papermc/paper/enchantments/EnchantmentRarity.java b/src/main/java/io/papermc/paper/enchantments/EnchantmentRarity.java
 new file mode 100644
@@ -97,6 +98,16 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
 +    public abstract int getMaxModifiedCost(int level);
 +
 +    /**
++     * Gets cost of applying this enchantment using an anvil.
++     * <p>
++     * Note that this is halved when using an enchantment book, and is multiplied by the level of the enchantment.
++     * See <a href="https://minecraft.wiki/w/Anvil_mechanics">https://minecraft.wiki/w/Anvil_mechanics</a> for more information.
++     * </p>
++     * @return The anvil cost of this enchantment
++     */
++    public abstract int getAnvilCost();
++
++    /**
 +     * Gets the rarity of this enchantment.
 +     *
 +     * @return the rarity