Allow manual color schemes about stylix

[dit7ya]

Is it possible to do manual colors now? Looking at the following, seems like it's a TODO?

stylix/stylix/palette.nix

Line 43 in f78eff2

/* TODO: Implement manual palette

[danth]

Hi, this was implemented and then made back into a TODO due to some implementation changes.

I can find some time to work on this at the weekend, as most of the code is already in place.

[Lyndeno]

For now I do this to use a manual scheme:

let
  base16Scheme = "${inputs.base16-schemes}/gruvbox-dark-hard.yaml";
in
{
  lib.stylix.colors = config.lib.base16.mkSchemeAttrs base16Scheme;
}

But a built in method to do so would be nice.

[danth]

@Lyndeno You should be able to use this new option now:

stylix.base16Scheme = "${inputs.base16-schemes}/gruvbox-dark-hard.yaml";