[openssl/openssl] a57ab4: Document return value of OSSL_DECODER_from_data

[openssl-machine]

  Branch: refs/heads/openssl-3.1
  Home:   https://github.com/openssl/openssl
  Commit: a57ab43975dc2ec0d1c813d9e037f0e58fac489d
      https://github.com/openssl/openssl/commit/a57ab43975dc2ec0d1c813d9e037f0e58fac489d
  Author: Benno Evers <benno at bourbaki>
  Date:   2023-02-21 (Tue, 21 Feb 2023)

  Changed paths:
    M doc/man3/OSSL_DECODER_from_bio.pod

  Log Message:
  -----------
  Document return value of OSSL_DECODER_from_data

CLA: trivial

Reviewed-by: Matt Caswell <matt at openssl.org>
Reviewed-by: Kurt Roeckx <kurt at roeckx.be>
Reviewed-by: Paul Dale <pauli at openssl.org>
(Merged from https://github.com/openssl/openssl/pull/20327)

(cherry picked from commit 7e5505107aacdf58a4d0c00da90af4b7407c8d65)