doc: add option to require 'process' to api docs

It is possible to require the 'process' module and with the upcoming
support for ES Modules, importing 'process' might be the more favorable
way for developers. This commit adds that option to the documentation.

PR-URL: https://github.com/nodejs/node/pull/26792


Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Myles Borins <myles.borins@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>