nix multi-line shebang is not handled by just

[oux]

Environment:

• nix 2.20.1 or later
• just 1.25.2

justfile:

hello:
  #!/usr/bin/env nix
  #! nix shell  nixpkgs#hello nixpkgs#cowsay --command bash
  hello | cowsay

Error:

Same shebang on a simple shell script file:

Nix shebang documentation: https://nixos.org/manual/nix/stable/command-ref/new-cli/nix.html#shebang-interpreter