doc: specify sorted requires in tests

And allow anchor links to the various sections, to more easily reference
them when reviewing PRs.

PR-URL: https://github.com/nodejs/node/pull/10716


Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Gibson Fahnestock <gibfahn@gmail.com>