tls13: Fix doc of mbedtls_ssl_session_get() - 1

The API has eventually not been changed to
return multiple tickets through multiple
subsequent call to it.

Signed-off-by: Ronald Cron <ronald.cron@arm.com>

include/mbedtls/ssl.h

@@ -4845,23 +4845,12 @@ const mbedtls_x509_crt *mbedtls_ssl_get_peer_cert(const mbedtls_ssl_context *ssl
  * \note           This function can handle a variety of mechanisms for session
  *                 resumption: For TLS 1.2, both session ID-based resumption and
  *                 ticket-based resumption will be considered. For TLS 1.3,
- *                 once implemented, sessions equate to tickets, and calling
- *                 this function multiple times will export the available
- *                 tickets one a time until no further tickets are available,
- *                 in which case MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE will
- *                 be returned.
- *
- * \note           Calling this function multiple times will only be useful
- *                 once TLS 1.3 is supported. For TLS 1.2 connections, this
- *                 function should be called at most once.
+ *                 sessions equate to tickets, and this function exports the
+ *                 last received ticket.
  *
  * \return         \c 0 if successful. In this case, \p session can be used for
  *                 session resumption by passing it to mbedtls_ssl_set_session(),
  *                 and serialized for storage via mbedtls_ssl_session_save().
- * \return         #MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE if no further session
- *                 is available for export.
- *                 This error is a non-fatal, and has no observable effect on
- *                 the SSL context or the destination session.
  * \return         Another negative error code on other kinds of failure.
  *
  * \sa             mbedtls_ssl_set_session()