module: partial doc removal of --experimental-modules

This removes `--experimental-modules` from showing up in `node -h`
and also removes the documentation from the man pages.

It will still work as a no-op, and is still included in cli.md

Refs: https://github.com/nodejs/modules/issues/502

PR-URL: https://github.com/nodejs/node/pull/32915


Reviewed-By: Guy Bedford <guybedford@gmail.com>
Reviewed-By: Geoffrey Booth <webmaster@geoffreybooth.com>
Reviewed-By: David Carlier <devnexen@gmail.com>
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Franziska Hinkelmann <franziska.hinkelmann@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>