Function is_submodule_active_for_fetch 

pub fn is_submodule_active_for_fetch(
    _repo: &Repository,
    config: &ConfigSet,
    _super_tree_oid: &ObjectId,
    _path: &str,
    submodule_name: &str,
) -> bool

Whether a submodule at path is active for fetch at super_oid (Git is_tree_submodule_active subset).