chore(l10n): Use numbered placeholders

Reported in Transifex.

Signed-off-by: rakekniven <2069590+rakekniven@users.noreply.github.com>

lib/Notification/Notifier.php

@@ -136,7 +136,7 @@ class Notifier implements INotifier {
 				}
 
 				$notification->setParsedSubject(
-					$l->t('The card "%s" on "%s" has reached its due date.', $params)
+					$l->t('The card "%1$s" on "%2$s" has reached its due date.', $params)
 				);
 				$notification->setRichSubject(
 					$l->t('The card {deck-card} on {deck-board} has reached its due date.'),