Add some corrections based on code review

-Add the DHM_ALT in an alphabetical order
-Close correctly the 'extern "C" { ...'

library/version_features.c

@@ -99,6 +99,9 @@ static const char *features[] = {
 #if defined(MBEDTLS_DES_ALT)
     "MBEDTLS_DES_ALT",
 #endif /* MBEDTLS_DES_ALT */
+#if defined(MBEDTLS_DHM_ALT)
+    "MBEDTLS_DHM_ALT",
+#endif /* MBEDTLS_DHM_ALT */
 #if defined(MBEDTLS_XTEA_ALT)
     "MBEDTLS_XTEA_ALT",
 #endif /* MBEDTLS_XTEA_ALT */
@@ -123,9 +126,6 @@ static const char *features[] = {
 #if defined(MBEDTLS_SHA512_ALT)
     "MBEDTLS_SHA512_ALT",
 #endif /* MBEDTLS_SHA512_ALT */
-#if defined(MBEDTLS_DHM_ALT)
-    "MBEDTLS_DHM_ALT",
-#endif /* MBEDTLS_DHM_ALT */
 #if defined(MBEDTLS_ECP_ALT)
     "MBEDTLS_ECP_ALT",
 #endif /* MBEDTLS_ECP_ALT */