nixos-render-docs-redirects: init

[GetPsyched]

A helper command to manipulate the redirects mapping to avoid having to do it manually.

As of writing, this is still a WIP, and I have mentioned a few concerns as review comments to make the discussion async.

[GetPsyched]

This is my initial draft which only tests the happy paths. I'll be hacking on ways to make this more robust while leaving this here to marinate.

[nixos-discourse]

This pull request has been mentioned on NixOS Discourse. There might be relevant details there:

https://discourse.nixos.org/t/breaking-changes-announcement-for-unstable/17574/69

[nixos-discourse]

This pull request has been mentioned on NixOS Discourse. There might be relevant details there:

https://discourse.nixos.org/t/splitting-the-nixpkgs-and-nixos-manuals-into-pages/55466/9

[fricklerhandwerk]

This should start with tests to specify what the interaction is supposed to be like, see detailed comments

[fricklerhandwerk]

Found an unspecified requirement: nrd will complain if you rename an identifier but don't also rename references. It would be very helpful if this helper tool also did something akin to

sed -i 's/<old>/<new>/g' **/*

but that needs a bit of smarts, because we have to capture old identifiers correctly (e.g. naively inserting foo and foo2 after already having renamed the "tag" location of foo but not the "ref" locations, will produce foo22 at the "tag").

So this is not blocking for this PR. You would get the identifier errors by nrd already, so this change doesn't make it strictly worse. It may mess with expectations though, because one may think such a command will just do the Right Thing for you already.

[fricklerhandwerk]

Merging, let's do further improvements in follow-up PRs.