Hide "Fail" prefix from failed messages

Hi @jlstrecker, thanks a lot for your patch.

Sadly, I think it wouldn't work on multi-language websites.

On our side, we use the translation feature of Drupal to remove those "Fail -" prefixes.

Oh, right! Good idea to use translations. I was able to add this in settings.php:

$settings['locale_custom_strings_en'][''] = [
  'Fail - @message' => '@message',
];

Thanks for the tip!