nixos/zwave-js: Add more detail to the description of `settings` (#456647)

      };

      default = { };

      description = ''

        Configuration settings for the generated config

        file.

        Configuration settings for the generated config file.

        This config is combined with the contents of `secretsConfigFile` and

        passed to zwave-js-server via `--config`. The project's README [1]

        states that the config must follow the Z-Wave JS config format [2].

        [1]: https://github.com/zwave-js/zwave-js-server/tree/master

        [2]: https://zwave-js.github.io/node-zwave-js/#/api/driver?id=zwaveoptions

        ::: {.warning}

        Secrets should go in `secretsConfigFile`. The contents of `settings` is

        written to the nix store, which is world-readable.

        :::

      '';

    };