Function submodule_name_for_path 

pub fn submodule_name_for_path(
    repo: &Repository,
    path: &str,
) -> Result<Option<String>>

Resolve the submodule logical name for an index path (.gitmodules submodule.<name>.path).

Returns None when the path is not listed as a submodule in .gitmodules (work tree file or index blob), matching Git’s submodule_from_path failure.