Change the color of the titlebar and borders if their color is set to the accent color and the accent color changes and some other improvements

[Valer100]

This PR makes the titlebars and window borders that are set to the accent color to change their color if the accent color changes.

Screen.Recording.2024-10-08.mp4

If you're wondering why the buttons of the demo program are following the accent color, I use a 3rd party program called AccentColorizer that colorizes window controls with the accent color.

I also made some improvements:

• Raise an exception if someone tries to set the titlebar or border color if the rainbow effect is active in a specific window
• Raise an exception if someone tries to apply the rainbow effect to the titlebar or border if it's already active in a specific window
• Raise an exception if someone tries to set the titlebar or the border color of a specific window to the accent color if it's already set to it

[Zingzy]

Will take a look, thanks for the contribution 😀

[Valer100]

You're welcome!