anchor.diff:        tls_private_key_path = mkOption {
           type = types.nullOr types.str;
           default = null;
  -        example = "/var/lib/matrix-synapse/homeserver.tls.key";
  +        example = "${cfg.dataDir}/homeserver.tls.key";
           description = ''
             PEM encoded private key for TLS. Specify null if synapse is not
             speaking TLS directly.
  
positive.code:       tls_dh_params_path = mkOption {
          type = types.nullOr types.str;
          default = null;
          example = "/var/lib/matrix-synapse/homeserver.tls.dh";
          description = ''
            PEM dh parameters for ephemeral keys
          '';
  
negative.code:   name: "${cfg.database_type}",
    args: {
      ${concatStringsSep ",\n    " (
        mapAttrsToList (n: v: "\"${n}\": ${builtins.toJSON v}") cfg.database_args
      )}
    }
  }
  