Turn comments of 1.3 record transforms into Doxygen documentation

Signed-off-by: Hanno Becker <hanno.becker@arm.com>
diff --git a/library/ssl_misc.h b/library/ssl_misc.h
index 174bad8..0b64e01 100644
--- a/library/ssl_misc.h
+++ b/library/ssl_misc.h
@@ -563,8 +563,8 @@
 #endif /* MBEDTLS_SSL_PROTO_DTLS */
 
 #if defined(MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL)
-    /* TLS 1.3 transforms for 0-RTT and encrypted handshake messages.
-     * Those pointers own the transforms they reference. */
+    /*! TLS 1.3 transforms for 0-RTT and encrypted handshake messages.
+     *  Those pointers own the transforms they reference. */
     mbedtls_ssl_transform *transform_handshake;
     mbedtls_ssl_transform *transform_earlydata;
 #endif /* MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL */