anchor.diff:        enable = mkOption {
           default = false;
           description = ''
  -          Whenever to configure Zsh as an interactive shell.
  +          Whether to configure zsh as an interactive shell.
           '';
           type = types.bool;
         };
  
positive.code:         type = types.lines;
        };
  
      };
  
    };
  
negative.code:         export HISTFILE=$HOME/.zsh_history
  
          setopt HIST_IGNORE_DUPS SHARE_HISTORY HIST_FCNTL_LOCK
  
          # Tell zsh how to find installed completions
          for p in ''${(z)NIX_PROFILES}; do
            fpath+=($p/share/zsh/site-functions $p/share/zsh/$ZSH_VERSION/functions)
          done
  
          ${if cfg.enableCompletion then "autoload -U compinit && compinit" else ""}
        '';
  
      };
  