[Editor-Only] After you save the scene object `obj` as an asset file and load it as `asset`, this method goes through all the serialized UnityEngine.Object fields which weren't saved and adds them as sub-assets. Returns true if any sub-assets were saved.

For example, creating a procedural UnityEngine.Mesh, assigning it to a UnityEngine.MeshFilter, and saving the object as a prefab would not save the mesh anywhere unless you call this method or UnityEditor.AssetDatabase.AddObjectToAsset(UnityEngine.Object,UnityEngine.Object).

public static bool SaveSubAssets(Object obj, Object asset)