Function path_control 

pub fn path_control<G, S>(
    key: &'static str,
    prompt: &'static str,
    directories: bool,
    files: bool,
    value: G,
    set_value: S,
) -> Control
where
    G: Fn(&App) -> String + 'static,
    S: Fn(String, &mut App) + 'static,

A path input with a Browse… button, for use inside a SettingRow.