Nix support

[phunehehe]

I may be able to open a PR later on, but want to open an issue before I forget.
It's like this in Pygments https://bitbucket.org/birkenfeld/pygments-main/pull-requests/267/add-nix-language-lexer/diff.

[sjmackenzie]

@phunehehe Oh I would love to see your merge request opened! It's quite nasty reading nix files on gitlab! 🍻

[stale]

This issue has been automatically marked as stale because it has not had any activity for more than a year. It will be closed if no additional activity occurs within the next 14 days.
If you would like this issue to remain open, please reply and let us know if the issue is still reproducible.

[pyrmont]

It looks like Nix support was subsequently added to Rouge. Please let us know if there are any problems with its implementation.