Patchelf inputs in hydra manual need updating

[cessationoftime]

Describe the bug The hydra manual located here: https://hydra.nixos.org/build/271467131/download/1/hydra/projects.html

Still references release.nix as an input for the patchelf project: https://github.com/NixOS/patchelf/blob/master/release.nix

Release.nix no longer exists, so the manual needs to be updated or the example replaced with the hello example from the hydra repo's README.md

[cessationoftime]

Ideally I think it should be replaced by a flake.nix example since that is what patchelf now uses and I have not seen a flake.nix example in the manual or README.md