doc: fix wrong response.end() at request.socket

PR-URL: https://github.com/nodejs/node/pull/19507


Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Shigeki Ohtsu <ohtsu@ohtsu.org>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>