doc: add note about the configuration option for the jitter source.

Reviewed-by: Tomas Mraz <tomas@openssl.org>
Reviewed-by: Shane Lontis <shane.lontis@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/25498)

doc/man7/EVP_RAND-JITTER.pod

@@ -44,6 +44,8 @@ A context for the seed source can be obtained by calling:
  EVP_RAND *rand = EVP_RAND_fetch(NULL, "JITTER", NULL);
  EVP_RAND_CTX *rctx = EVP_RAND_CTX_new(rand, NULL);
 
+The B<enable-jitter> option was added in OpenSSL 3.4.
+
 =head1 EXAMPLES
 
  EVP_RAND *rand;