Pack overlays in mod files are not supported

[Apollounknowndev]

Minecraft Version: 1.20.2+

NeoForge Version: any

Description of issue: Pack overlays in mod pack.mcmeta files do not function. This is a major issue for datapacks-packaged-as-mods which rely on overlays to function correctly on new versions, such as Terralith.

Steps to Reproduce

• Install Terralith v2.4.11. This version of Terralith relies on pack overlays to support the minecraft:grass -> minecraft:short_grass change.
• Attempt to create a new world. The game will instantly crash due to errors with registries failing the load, which is due to the game still trying to parse the files with minecraft:grass in them.

[KnightMiner]

I assume #367 already addresses this issue. Due to the nature of the fix will require being part of a breaking changes window.

[lukebemish]

If #367 doesn't already address this issue I will be making sure it does before it's merged (which should be pretty easy if it doesn't already support it out of the box - it's supposed to but it's also untested so I might need to fix s thing or two) - avoiding this sort of issue is a major goal of that PR

[lukebemish]

Just tested locally and #367 does seem to fix this - at least, making the terralith jar use lowcodefml so that it would load, then loading it locally with that PR, loaded and generated a world with the overlays applied correctly.

[XFactHD]

Fixed by #367