Highlight group for out of focus window

[catgoose]

I use show_in_active_only currently, but I would like to be able to set a highlight group for the scrollbar in inactive windows instead of hiding it. There is already a highlight option to set the highlight group, maybe this can be expanded to be:

{
  handle = {
    highlight = "CursorLine",
    inactive_highlight = "CursorLine",
  }
}