Fix Nix build & direnv config

[x10an14]

• flake: Update inputs
• fix(direnv): Specify shell w/shebang + use direnv stdlib + use correct syntax
• flake: Simplify input dependencies
• refactor(flake): Add formatter for nix + tidy up flake
• fix(flake): Nix builds release + always specifies target triple

Description of changes

• Updated inputs used in nix flake (tool that defines the nix package of nufmt)
• Added formatter for nix flake/nix code
• Simplified nix flake's inputs/dependencies (synchronized and deduplicated)
• Tidied up/fixed .envrc file/direnv
• Fixed build broken by new tests added in Read config file, parallel file processing, exit codes, check mode, exclude files #69

Relevant Issues

None

[132ikl]

thanks for making that change! could you fix clippy, and then I think we're good to go on this

[x10an14]

thanks for making that change! could you fix clippy, and then I think we're good to go on this

Done in fced6a0 =)

Feels like I touched a lot of code that clippy complained about that I haven't touched though...

[132ikl]

seems like it's still complaining..? not sure why you had to make so many changes, seems like something is afoot

[x10an14]

Ahhh, I see what happened now.

I ran clippy w/some configured defaults, since at first I gave up getting the incantation at https://github.com/x10an14/nufmt/blob/7487a1f5731626f9296b6e2359c3bb8392f36f7d/.github/workflows/pull_request.yml#L26 to work for me locally.

I tried again with some more hand-rolling effort, and now I see that my local output matches (I didn't think to check previously, hence the big commit of unrelated clippy fixes, mea culpa) the previous runs' error(s).

[132ikl]

could you reduce the clippy changes to just what's relevant to this PR? I'm not opposed to the clippy changes resulting from your config necessarily but it doesn't seem appropriate to put them in a PR for fixing the Nix build, especially when some of them include function signature changes

[x10an14]

could you reduce the clippy changes to just what's relevant to this PR? (...)

Done in 2809ce2.

Feel free to revert the revert if y'all want em after all.

[132ikl]

thanks! let's get this merged finally 😄