anchor.diff:        '';
       };
   
  -    nixpkgs.system = mkOption {
  +    system = mkOption {
         type = types.str;
         example = "i686-linux";
         description = ''
  
positive.code: in
  
  {
    options = {
  
      nixpkgs.config = mkOption {
        default = {};
        example = literalExample
          ''
  
negative.code:       '';
      };
  
      overlays = mkOption {
        default = [];
        example = literalExample
          ''
  