Add ItemType#getBurnDuration() (#12604)

paper-api/src/main/java/org/bukkit/inventory/ItemType.java

@@ -3021,9 +3021,18 @@ public interface ItemType extends Keyed, Translatable, net.kyori.adventure.trans
      * Checks if this item type can be used as fuel in a Furnace
      *
      * @return true if this item type can be used as fuel.
+     * @see #getBurnDuration() 
      */
     boolean isFuel();
 
+    /**
+     * Retrieve the item's burn duration in a Furnace
+     * 
+     * @return the burn duration, in ticks or 0 if the item is not fuel
+     * @see #isFuel()
+     */
+    int getBurnDuration();
+
     /**
      * Checks whether this item type is compostable (can be inserted into a
      * composter).