crate leaks incredible amounts of memory on macOS

[sporeball]

this crate is being used in hackclub/kicad-wakatime, which has been suffering a memory leak for quite some time (tracking issue kicad-wakatime #3). using the Instruments tool on macOS, i've finally isolated the leak to this crate.
kicad-wakatime needs to call get_active_window() repeatedly, which leads to the leak.

i am not sure if the memory leak is present on other operating systems, but on macOS, users have reported potential memory usage of up to 30GB after a few hours.

[sporeball]

i think i managed to find where the leak is coming from.

after the last call to get_from_dict():

if let DictEntryValue::_Number(window_id) =
    get_from_dict(dic_ref, "kCGWindowNumber")
{
    let active_window = ActiveWindow {
        window_id: window_id.to_string(),
        process_id: active_window_pid as u64,
        app_name,
        position: win_pos,
        title: win_title,
        process_path,
    };

    return Ok(active_window);
}

CFRelease(window_list_info as CFTypeRef) is not called there - it's only called when the crate is about to return Err(()). add a CFRelease() call just above return Ok(active_window), and the leak is no longer reproducible.