[openssl/openssl] a6f460: add note about retrieving error stack

[Vladimir Kotal]

  Branch: refs/heads/openssl-3.1
  Home:   https://github.com/openssl/openssl
  Commit: a6f46005413b49265aa91b2e00930a17b494df78
      https://github.com/openssl/openssl/commit/a6f46005413b49265aa91b2e00930a17b494df78
  Author: Vladimír Kotal <vladimir.kotal at oracle.com>
  Date:   2023-06-26 (Mon, 26 Jun 2023)

  Changed paths:
    M doc/man3/SSL_get_verify_result.pod

  Log Message:
  -----------
  add note about retrieving error stack

Reviewed-by: Tomas Mraz <tomas at openssl.org>
Reviewed-by: Paul Dale <pauli at openssl.org>
(Merged from https://github.com/openssl/openssl/pull/21220)

(cherry picked from commit a7c54dde5189f11c046f638e5aaf2004aee34202)