doc: fix typo in `async_hooks.md`

PR-URL: https://github.com/nodejs/node/pull/40187


Reviewed-By: Qingyu Deng <i@ayase-lab.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Zijian Liu <lxxyxzj@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>