doc: fix YAML comment opening tags

Several YAML documentation comments incorrectly started with `<!--YAML`
instead of `<!-- YAML`, resulting in their content missing in the
rendered documentation.

PR-URL: https://github.com/nodejs/node/pull/38324


Reviewed-By: Richard Lau <rlau@redhat.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>
Reviewed-By: Darshan Sen <raisinten@gmail.com>