doc: esm loader example with module.builtinModules

PR-URL: https://github.com/nodejs/node/pull/17385


Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Jon Moss <me@jonathanmoss.me>
Reviewed-By: Timothy Gu <timothygu99@gmail.com>