postfix service: typo in transport filepath

  // optionalAttrs (cfg.relayDomains != null) { relay_domains = cfg.relayDomains; }

  // optionalAttrs (cfg.recipientDelimiter != "") { recipient_delimiter = cfg.recipientDelimiter; }

  // optionalAttrs haveAliases { alias_maps = "${cfg.aliasMapType}:/etc/postfix/aliases"; }

  // optionalAttrs haveTransport { transport_maps = "hash:/etc/postfx/transport"; }

  // optionalAttrs haveTransport { transport_maps = "hash:/etc/postfix/transport"; }

  // optionalAttrs haveVirtual { virtual_alias_maps = "${cfg.virtualMapType}:/etc/postfix/virtual"; }

  // optionalAttrs (cfg.dnsBlacklists != []) { smtpd_client_restrictions = clientRestrictions; }

  // optionalAttrs cfg.enableHeaderChecks { header_checks = "regexp:/etc/postfix/header_checks"; }