The Nix CLI is inconsistent with the --command flag...

We would transform (e.g.) nix develop -L .#ghc942 into nix develop --command fish -L .#ghc942, which Nix interprets as running the command fish -L .#ghc942 in the shell. This patch puts the --command fish bit at the end, instead of at the front, so the -L .#ghc942 arguments are correctly passed to nix develop.

Future work: actually writing some tests lol

I get the following error log:

$ RUST_BACKTRACE=1 nix run github:MercuryTechnologies/nix-your-shell -- zsh | source
source: not enough arguments
The application panicked (crashed).
Message:  failed printing to stdout: Broken pipe (os error 32)
Location: library/std/src/io/stdio.rs:1009

  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ BACKTRACE ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
                                ⋮ 7 frames hidden ⋮
   8: std::io::stdio::_print::h8161ac4f19406cdf
      at <unknown source file>:<unknown line>
   9: nix_your_shell::main::h1ef7ab779e977552
      at <unknown source file>:<unknown line>
  10: std::sys_common::backtrace::__rust_begin_short_backtrace::h50a6c336720655bd
      at <unknown source file>:<unknown line>
  11: std::rt::lang_start::{{closure}}::h4580b04423cddd21
      at <unknown source file>:<unknown line>
  12: std::rt::lang_start_internal::h398023bd7970a80b
      at <unknown source file>:<unknown line>
  13: main<unknown>
      at <unknown source file>:<unknown line>
  14: __libc_start_call_main<unknown>
      at <unknown source file>:<unknown line>
  15: __libc_start_main_alias_1<unknown>
      at <unknown source file>:<unknown line>
  16: _start<unknown>
      at <unknown source file>:<unknown line>

Run with COLORBT_SHOW_HIDDEN=1 environment variable to disable frame filtering.
Run with RUST_BACKTRACE=full to include source snippets.

This also happens with fish.

This fixes extra arguments. Before, you'd see this if you tried to use any arguments with nix-shell or nix develop:

$ nix develop --command whatever
error: unexpected argument '--command' found

  note: to pass '--command' as a value, use '-- --command'

Usage: nix-your-shell <SHELL> nix <ARGS>

For more information, try '--help'.

It got picked up by repology so we can add this badge too now! Although curiously it hasn't actually landed on nixpkgs yet: https://nixpk.gs/pr-tracker.html?pr=215733

1. zsh source requires a filename, so we use nix-your-shell zsh | source /dev/stdin instead.
2. nix-your-shell zsh was printing the fish code instead of the zsh code due to a copy-pasting error (lol). Fix that.

Also clean up the README a bit.

Closes #4

cargo-dist is neat but can't yet produce universal macOS binaries; see https://github.com/axodotdev/cargo-dist/issues/77

Remove it for now

This will have to wait on getting the self-hosted runners added

The basic workflow is:

• Label PRs with patch, minor, or major
• When PRs are merged, version numbers are bumped automatically and a new PR is opened, labeled release
• When a release PR is merged, a release is cut and built and published automatically

This is a little weird, because bash is the default shell Nix uses. However, we're currently seeing a bug where nix develop will exit if any command being run exits with a nonzero exit code, but nix develop --command bash will not. Weird!

EDIT: The bug was caused by sourcing scripts created with writeShellApplication instead of writeShellScriptBin in the Nix shell's shellHook, causing set -eu being sourced at the beginning of the shell. This in turn caused any failing command to exit the shell. I'm still going to merge this though because bash support won't hurt anyone.