doc: sort bottom-of-file markdown links

Reapply https://github.com/nodejs/node/pull/12726

It would be nice to have the sort check applied as part of doc testing,
but this change doesn't implement that.

PR-URL: https://github.com/nodejs/node/pull/24679


Reviewed-By: Vse Mozhet Byt <vsemozhetbyt@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>