tls13: Align some debug messages with TLS 1.2 ones

Signed-off-by: Ronald Cron <ronald.cron@arm.com>
diff --git a/library/ssl_tls13_generic.c b/library/ssl_tls13_generic.c
index f508bca..acd227d 100644
--- a/library/ssl_tls13_generic.c
+++ b/library/ssl_tls13_generic.c
@@ -567,7 +567,7 @@
      */
     if( ssl->session_negotiate->peer_cert == NULL )
     {
-        MBEDTLS_SSL_DEBUG_MSG( 1, ( "peer has not sent a certificate" ) );
+        MBEDTLS_SSL_DEBUG_MSG( 1, ( "peer has no certificate" ) );
 
 #if defined(MBEDTLS_SSL_SRV_C)
         if( ssl->conf->endpoint == MBEDTLS_SSL_IS_SERVER )