fix /bin/wslpath missing

[nzbr]

Fixes #104

[SuperSandro2000]

That only kinda works when doing PATH=$PATH:/bin code .

NixOS does not include /bin into $PATH by default but adding it is also not necessary since wslpath only cares about the symlink name, not the path. So it should be enough to create a basic package which symlinks /init to $out/bin/wslpath

[SuperSandro2000]

something like this

environment.systemPackages = [
(pkgs.writeShellScript "wslpath" ''
  ln -rs /init $out/bin/wslpath
'';)
];