doc: unify place of stability notes

In most cases, stability note is the first info in a doc section
after YAML. This PR makes it consistent across all docs,
as this info seems the most relevant for a reader.

PR-URL: https://github.com/nodejs/node/pull/29799


Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: David Carlier <devnexen@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>