Describe new callback for session id generation.
diff --git a/doc/ssl/ssl.pod b/doc/ssl/ssl.pod
index f275519..50f8d86 100644
--- a/doc/ssl/ssl.pod
+++ b/doc/ssl/ssl.pod
@@ -663,6 +663,7 @@
L<SSL_CTX_sessions(3)|SSL_CTX_sessions(3)>,
L<SSL_CTX_set_client_CA_list(3)|SSL_CTX_set_client_CA_list(3)>,
L<SSL_CTX_set_default_passwd_cb(3)|SSL_CTX_set_default_passwd_cb(3)>,
+L<SSL_CTX_set_generate_session_id(3)|SSL_CTX_set_generate_session_id(3)>,
L<SSL_CTX_set_mode(3)|SSL_CTX_set_mode(3)>,
L<SSL_CTX_set_options(3)|SSL_CTX_set_options(3)>,
L<SSL_CTX_set_session_cache_mode(3)|SSL_CTX_set_session_cache_mode(3)>,
