doc: edit Error.captureStackTrace html comment

Edit to the comment in the stack trace capture, highlighting the use of
the constructorOpt argument in errors.md

Fixes: https://github.com/nodejs/node/issues/12289
PR-URL: https://github.com/nodejs/node/pull/12962


Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>
Reviewed-By: Ruben Bridgewater <ruben.bridgewater@fintura.de>