doc: remove recommendation to use node-eps

https://github.com/nodejs/node-eps has been archived and new proposals
can no longer be opened there. Remove the corresponding recommendation
to use it.

PR-URL: https://github.com/nodejs/node/pull/23148
Refs: https://github.com/nodejs/TSC/issues/335


Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Gus Caplan <me@gus.host>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Sakthipriyan Vairamani <thechargingvolcano@gmail.com>