doc: improve async_hooks asynchronous context example

* use writeFile(1) everywhere to log
* prettify execution id graph
* add clearer explanation for TickObject presence
* add causation graph via triggerAsyncId

PR-URL: https://github.com/nodejs/node/pull/33730


Reviewed-By: Gerhard Stöbich <deb2001-github@yahoo.de>
Reviewed-By: Andrey Pechkurov <apechkurov@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Vladimir de Turckheim <vlad2t@hotmail.com>