update docs of ssl_client2 and improve code format

Signed-off-by: Pengyu Lv <pengyu.lv@arm.com>
diff --git a/library/ssl_tls13_server.c b/library/ssl_tls13_server.c
index acb1523..ef90f69 100644
--- a/library/ssl_tls13_server.c
+++ b/library/ssl_tls13_server.c
@@ -172,10 +172,11 @@
     ret = MBEDTLS_ERR_ERROR_GENERIC_ERROR;
     MBEDTLS_SSL_PRINT_TICKET_FLAGS(4,
                                    session->ticket_flags);
-    if (mbedtls_ssl_tls13_check_kex_modes(ssl,
-                                          mbedtls_ssl_session_get_ticket_flags(
-                                              session,
-                                              MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK_ALL))) {
+    if (mbedtls_ssl_tls13_check_kex_modes(
+            ssl,
+            mbedtls_ssl_session_get_ticket_flags(
+                session,
+                MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK_ALL))) {
         MBEDTLS_SSL_DEBUG_MSG(3, ("No suitable key exchange mode"));
         goto exit;
     }