implement Ingredient.getSerializer for custom ingredients (#5813)

src/main/java/net/minecraftforge/common/crafting/CompoundIngredient.java

@@ -107,6 +107,12 @@ public class CompoundIngredient extends Ingredient
         return isSimple;
     }
 
+    @Override
+    public IIngredientSerializer<? extends Ingredient> getSerializer()
+    {
+        return CraftingHelper.INGREDIENT_COMPOUND;
+    }
+
     @Nonnull
     public Collection<Ingredient> getChildren()
     {

src/main/java/net/minecraftforge/common/crafting/IngredientNBT.java

@@ -53,6 +53,12 @@ public class IngredientNBT extends Ingredient
         return false;
     }
 
+    @Override
+    public IIngredientSerializer<? extends Ingredient> getSerializer()
+    {
+        return CraftingHelper.INGREDIENT_NBT;
+    }
+
     public static class Serializer implements IIngredientSerializer<IngredientNBT>
     {
         @Override