SPIGOT-4283: Allow setting recipe groups

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

paper-server/nms-patches/FurnaceRecipe.patch

@@ -11,7 +11,7 @@
  
  public class FurnaceRecipe implements IRecipe {
  
-@@ -56,6 +60,16 @@
+@@ -56,6 +60,19 @@
          return this.key;
      }
  
@@ -22,13 +22,16 @@
 +        list.buildChoices();
 +        net.minecraft.server.ItemStack stack = list.choices[0];
 +
-+        return new CraftFurnaceRecipe(CraftNamespacedKey.fromMinecraft(this.key), result, CraftItemStack.asCraftMirror(stack), this.experience, this.cookingTime);
++        CraftFurnaceRecipe recipe = new CraftFurnaceRecipe(CraftNamespacedKey.fromMinecraft(this.key), result, CraftItemStack.asCraftMirror(stack), this.experience, this.cookingTime);
++        recipe.setGroup(this.group);
++
++        return recipe;
 +    }
 +
      public static class a implements RecipeSerializer<FurnaceRecipe> {
  
          public a() {}
-@@ -106,11 +120,11 @@
+@@ -106,11 +123,11 @@
              return "smelting";
          }