doc: document x509 error codes

Signed-off-by: Dan Čermák <dcermak@suse.com>
Co-authored-by: Antoine du Hamel <duhamelantoine1995@gmail.com>
Co-authored-by: James M Snell <jasnell@gmail.com>

PR-URL: https://github.com/nodejs/node/pull/37096
Fixes: https://github.com/nodejs/node/issues/29342
Fixes: https://github.com/nodejs/node/issues/29342


Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>