Add the NixOS unofficial wiki to unofficial sources (https://nixos.wiki/wiki/)

[ahydronous]

Introduce your stance
The unofficial wiki is a great (if sometimes outdated) source for configuring NixOS. It often has helpful code blurbs.

Describe the issue
https://nixos.wiki/wiki is currently not in the unofficial sources.

Page links
https://nixos.org/community/

• I already created a Pull Request

[mschwaig]

The unofficial wiki has been superseded by the official one.

As far as I am aware all of the content has been migrated, but the person running the unofficial wiki is not responsive to cooperating with that effort. So it would be kind of counter-productive to link the unofficial wiki anywhere.

You can read more about that at NixOS/foundation#113 and https://wiki.nixos.org/wiki/NixOS_Wiki:History.