Not all available groups are defined because the rest seem to look good with default links/definitions.
Colors for 'mini.indentscope', 'mini.jump2d', and 'mini.statusline' are using 'indent-blankline.nvim', 'hop.nvim', and 'lualine.nvim' for reference.
Colors for 'mini.icons' are taken as the closest in hue to the hue in name.
Groups for 'mini.test' are present just in case, because their default colors are inferred from vim.g.terminal_color_{1,2} which is not really clean.
Others mostly follow how I prefer those groups to be colored. So a matter of preference how they should be colored, just not as from default links (for better usability).
This PR adds explicit support for 'echasnovski/mini.nvim'. Some notes:
vim.g.terminal_color_{1,2}
which is not really clean.