Delete unused config file for shells

shells/default/default.nix

@@ -1,15 +0,0 @@
-{
-  # Snowfall Lib provides a customized `lib` instance with access to your flake's library
-  # as well as the libraries available from your flake's inputs.
-  lib,
-  # You also have access to your flake's inputs.
-  inputs,
-  # All other arguments come from NixPkgs. You can use `pkgs` to pull shells or helpers
-  # programmatically or you may add the named attributes as arguments here.
-  pkgs,
-  stdenv,
-  ...
-}:
-pkgs.mkShell {
-  # Create your shell
-}