Add missing asterisk to doxygen closures

Clarify section names next to closing braces
Signed-off-by: Andrzej Kurek <andrzej.kurek@arm.com>
diff --git a/include/mbedtls/asn1.h b/include/mbedtls/asn1.h
index 4746c1c..b64af10 100644
--- a/include/mbedtls/asn1.h
+++ b/include/mbedtls/asn1.h
@@ -58,7 +58,7 @@
 /** Buffer too small when writing ASN.1 data structure. */
 #define MBEDTLS_ERR_ASN1_BUF_TOO_SMALL                    -0x006C
 
-/* \} name */
+/** \} name ASN1 Error codes */
 
 /**
  * \name DER constants
@@ -118,8 +118,8 @@
 #define MBEDTLS_ASN1_TAG_PC_MASK             0x20
 #define MBEDTLS_ASN1_TAG_VALUE_MASK          0x1F
 
-/* \} name */
-/* \} addtogroup asn1_module */
+/** \} name DER constants */
+/** \} addtogroup asn1_module */
 
 /** Returns the size of the binary string, without the trailing \\0 */
 #define MBEDTLS_OID_SIZE(x) (sizeof(x) - 1)
@@ -626,6 +626,8 @@
  */
 void mbedtls_asn1_free_named_data_list( mbedtls_asn1_named_data **head );
 
+/** \} name Functions to parse ASN.1 data structures */
+
 #ifdef __cplusplus
 }
 #endif