Automatically update nix manual

[Mic92]

based on #1142

[Mic92]

Example run in https://github.com/Mic92/nix.dev/actions/runs/15225237797/job/42826435933

[fricklerhandwerk]

Thanks! I don't see why we should run an update every day though, seems very wasteful. Before the automation I ran the command manually around each release and it was fine. We may as well do a workflow_dispatch and add a line to the Nix release instructions to hit that button on GitHub. Once we migrate Nixpkgs/NixOS manuals here, we can do the same for stable and only bump unstable every 24h.

[Mic92]

Do you think so? It may just run a minute or so. Probably peanuts compared to what we do in nixpkgs. I got complaints about the missing manual in less then 24h. The idea was that we never have to run this again manually. I wasn't even aware of this process until someone told me the manual is out of date.

[fricklerhandwerk]

Just because we're likely burning embarrassing amounts of ancient phytoplankton with Nixpkgs doesn't mean that it's alright or that we have to do any more of that... We probably can't simply make it pull-based, but should be easy enough to add gh repo clone nixos/nix.dev && cd nix.dev && gh workflow run ... to the release script (or at least the manual steps), no?

[Mic92]

If you want to stay on top of these things? For the last release it was delayed. Personally I find my time more valuable than some github action that runs every now and than.