nix(home-manager) refactor settings option to be more "nix-like"

[invra]

Personally, I have my own home-manager module which I have created due to the current one I see as really sloppy, works, but a lazy solution. I would think the way I have mine would be nice, which is basically just what the Hyprland home-manager does, that has a type which will allow anything inside of wayland.windowManager.mango then use generators.toKeyValue, which allows expressions like

exec-once = "${pkgs.waybar}/bin/waybar"
exec-once = "${pkgs.mako}/bin/mako"
exec-once = "${pkgs.swww}/bin/swww-daemon"

to be like;

exec-once = [
  "${pkgs.waybar}/bin/waybar"
  "${pkgs.mako}/bin/mako"
  "${pkgs.swww}/bin/swww-daemon"
];

my module as an example of what the settings option might look like

I wonder if this should be something I should make a PR for, and if it would be welcome?