[openssl/openssl] c69756: doc: note that out ChaCha20 isn't standard compliant.

[Pauli]

  Branch: refs/heads/master
  Home:   https://github.com/openssl/openssl
  Commit: c69756e7a0133b67df50525e89206c9cc4a7d2b8
      https://github.com/openssl/openssl/commit/c69756e7a0133b67df50525e89206c9cc4a7d2b8
  Author: Pauli <pauli at openssl.org>
  Date:   2023-06-06 (Tue, 06 Jun 2023)

  Changed paths:
    M doc/man3/EVP_chacha20.pod

  Log Message:
  -----------
  doc: note that out ChaCha20 isn't standard compliant.

Fixes #21095

Reviewed-by: Tomas Mraz <tomas at openssl.org>
Reviewed-by: Shane Lontis <shane.lontis at oracle.com>
(Merged from https://github.com/openssl/openssl/pull/21098)