improve document

Signed-off-by: Jerry Yu <jerry.h.yu@arm.com>
diff --git a/include/mbedtls/ssl.h b/include/mbedtls/ssl.h
index ad5fbc5..8e187dd 100644
--- a/include/mbedtls/ssl.h
+++ b/include/mbedtls/ssl.h
@@ -1253,7 +1253,7 @@
 #endif /*  MBEDTLS_SSL_PROTO_TLS1_3 && MBEDTLS_SSL_SESSION_TICKETS */
 
 #if defined(MBEDTLS_SSL_EARLY_DATA)
-    uint32_t MBEDTLS_PRIVATE(max_early_data_size);          /*!< max_early_data_size of ticket */
+    uint32_t MBEDTLS_PRIVATE(max_early_data_size);          /*!< maximum amount of early data in tickets */
 #endif
 
 #if defined(MBEDTLS_SSL_ENCRYPT_THEN_MAC)
@@ -2042,6 +2042,10 @@
  *
  * \warning This interface is experimental and may change without notice.
  *
+ * \warning This interface DOES NOT influence/limit the amount of early data
+ *          that can be received with tickets that were previously created and
+ *          emitted and that clients may have stored.
+ *
  */
 void mbedtls_ssl_tls13_conf_max_early_data_size(
     mbedtls_ssl_config *conf, uint32_t max_early_data_size);