doc: remove errors that were never released

Refs: https://github.com/nodejs/node/pull/33764#issuecomment-653667275

PR-URL: https://github.com/nodejs/node/pull/34197


Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>