Function autoload

fn autoload<'ob>(
    function: Symbol<'ob>,
    file: &str,
    docstring: Option<Gc<ObjectType<'_>>>,
    interactive: Option<Gc<ObjectType<'_>>>,
    load_type: Option<Gc<ObjectType<'_>>>,
    cx: &'ob Context<'_>,
) -> Result<Symbol<'ob>>