Bug: value of DWMWA_USE_IMMERSIVE_DARK_MODE changed on newer Windows version

[ngxson]

Description:

On windows, the SetBrightness controls the flag DWMWA_USE_IMMERSIVE_DARK_MODE as shown here: https://github.com/leanflutter/window_manager/blob/main/windows/window_manager.cpp#L1002

The value of DWMWA_USE_IMMERSIVE_DARK_MODE is hard coded to 19 in the same file: https://github.com/leanflutter/window_manager/blob/main/windows/window_manager.cpp#L31

However, in the official documentation, this value has been changed to 20: https://learn.microsoft.com/en-us/windows/win32/api/dwmapi/ne-dwmapi-dwmwindowattribute

Impact:

The title bar on windows 11 (light mode) does not display correctly, as seen in #385

Note:

Please also follow this discussion for more information: mintty/mintty#983