Support Nix 2.4

[SuperSandro2000]

so far only tested it with basic commands but it works better then before where the current line was cleared.

[ncfavier]

Nix 2.4 has its own completion script which collides with nix-bash-completions.

Maybe it would be better to remove completion for the nix command altogether when the Nix version is at least 2.4?

[SuperSandro2000]

I did that in an overlay where I combined the old and new one.

[SuperSandro2000]

final: prev: {
  nix-bash-completions = prev.nix-bash-completions.overrideAttrs (oldAttrs: {
    patches = [
      # nom-build
      (final.fetchpatch {
        url = "https://github.com/hedning/nix-bash-completions/commit/2861e9b1b7351b77852444a79d164469ebbedd52.patch";
        sha256 = "sha256-L3NhFbnKwqP8+DaqG2/cufjQU7fuNhmXNMaC9m0YDEg=";
      })
      # nix 2.4 support
      (final.fetchpatch {
        url = "https://github.com/hedning/nix-bash-completions/commit/5d28f3de9244ccf679630770b90448a22a65aced.patch";
        sha256 = "sha256-Kez20a8YMvUe8lDVmzDCC8OmNX3taUMtjy917whlPUU=";
      })
    ];

    postPatch = ''
      substituteInPlace _nix \
        --replace "nix nixos-option" "nixos-option"

      cat ${prev.nixUnstable}/share/bash-completion/completions/nix >> _nix
    '';
  });
}

[bjornfor]

so far only tested it with basic commands but it works better then before where the current line was cleared.

Here's another PR that fixes "TAB completion erases line": #21