doxygen: move addtogroup closures to include more elements

Signed-off-by: Andrzej Kurek <andrzej.kurek@arm.com>
diff --git a/include/mbedtls/x509.h b/include/mbedtls/x509.h
index 3bce4de..31b78df 100644
--- a/include/mbedtls/x509.h
+++ b/include/mbedtls/x509.h
@@ -255,7 +255,6 @@
 mbedtls_x509_time;
 
 /** \} name Structures for parsing X.509 certificates, CRLs and CSRs */
-/** \} addtogroup x509_module */
 
 /**
  * \brief          Store the certificate DN in printable form into buf;
@@ -311,6 +310,8 @@
  */
 int mbedtls_x509_time_is_future( const mbedtls_x509_time *from );
 
+/** \} addtogroup x509_module */
+
 #if defined(MBEDTLS_SELF_TEST)
 
 /**