[1.19.3] Add ability to datagen forge specific values in pack.mcmeta (#9221)

Co-authored-by: sciwhiz12 <sciwhiz12@gmail.com>

src/main/java/net/minecraftforge/common/ForgeHooks.java

@@ -55,6 +55,7 @@ import net.minecraft.network.chat.TextColor;
 import net.minecraft.network.chat.contents.LiteralContents;
 import net.minecraft.server.level.ServerLevel;
 import net.minecraft.server.packs.PackType;
+import net.minecraft.server.packs.metadata.pack.PackMetadataSection;
 import net.minecraft.tags.BlockTags;
 import net.minecraft.tags.TagEntry;
 import net.minecraft.tags.TagKey;
@@ -1520,7 +1521,7 @@ public class ForgeHooks
 
         for (PackType packType : PackType.values())
         {
-            String key = "forge:" + packType.bridgeType.name().toLowerCase(Locale.ROOT) + "_pack_format";
+            String key = makePackFormatKey(packType);
             if (json.has(key))
             {
                 map.put(packType, GsonHelper.getAsInt(json, key));
@@ -1530,6 +1531,24 @@ public class ForgeHooks
         return map.buildOrThrow();
     }
 
+    public static void writeTypedPackFormats(JsonObject json, PackMetadataSection section)
+    {
+        int packFormat = section.getPackFormat();
+        for (PackType packType : PackType.values())
+        {
+            int format = section.getPackFormat(packType);
+            if (format != packFormat)
+            {
+                json.addProperty(makePackFormatKey(packType), format);
+            }
+        }
+    }
+
+    private static String makePackFormatKey(PackType packType)
+    {
+        return "forge:" + packType.bridgeType.name().toLowerCase(Locale.ROOT) + "_pack_format";
+    }
+
     /**
      * <p>
      *    This method is used to prefix the path, where elements of the associated registry are stored, with their namespace, if it is not minecraft