Introduce nixf-tidy

[kachick]

nix-community/nixd#497
https://discourse.nixos.org/t/list-of-nix-linters/19279/9
NixOS/nixpkgs#330066
NixOS/nixpkgs#332695
https://github.com/inclyc/flakes/blob/168b2fb0c66c9946037afaf1b4bb884e3b58b465/.github/workflows/nixf-tidy.yml#L25C13-L25C36

[kachick]

💭 Without this, zed and the default nixd integration displays many warnings

[kachick]

Draft

git ls-files '*.nix' | xargs -I{} bash <<'BASH'
echo -n '{}: '
git diff --exit-code --quiet <(printf '[]\n') <(<{} nixf-tidy --pretty-print --variable-lookup)
echo "$?"
BASH


git ls-files '*.nix' | xargs -I{} bash <(<<'BASH'
echo -n "$1: "
BASH
) {}


git ls-files '*.nix' | xargs -I{} bash -c '
echo -n "{}: "
git diff --exit-code --quiet <(printf "[]\n") <(<{} nixf-tidy --pretty-print --variable-lookup)
echo "$?"
'