Add explicit support for 'mini.nvim'

Hi! I would like to add explicit support for mini.nvim.

Basic choices are taken from highlight groups to which 'mini.nvim' makes links by default or from analogous plugins.

Differences from default linked groups:

'mini.cursorword' is based on 'Illuminate'.
'mini.jump2d' is based on 'Hop'.
'mini.starter' is based on 'dashboard.lua' and personal choices:
- MiniStarterItemBullet is as border.
- MiniStarterItemPrefix and MiniStarterQuery are based on "warning" and "info" diagnostic colors to be opposite of each other.
- MiniStarterSection is chosen to be visible.
'mini.statusline' is based on 'lualine/themes/tokyonight.lua' and personal choices:
- MiniStatuslineDevinfo and MiniStatuslineFileinfo have slightly different background.
- All MiniStatuslineMode* have bold text to increase visibility.
- MiniStatuslineModeOther is chosen from terminal mode.
'mini.tabline' is based on explicit 'TabLine*' groups:
- MiniTablineCurrent has bold font to be visually distinctive.
- MiniTablineVisible has slightly darker background than MiniTablineCurrent.
- MiniTablineTabpagesection is chosen from Search but with bold style to be visible.
- MiniTablineModified* groups have inverted fg and bg of their counterparts.
'mini.test' has red for fail and green for pass.
'mini.trailspace' has group with red background to draw attention.

Before:

After:

projekt0n / github-nvim-theme