Plural form in print_mail.inc

I'm working on translating the module and found out that line 30-33 in print_mail.inc does not count for the plural form.

It's currently

<?php
$form['flood'] = array(
     '#type' => 'markup',
     '#value' => '<p>'. t('You cannot send more than %number messages per hour. Please try again later.', array('%number' => $print_mail_hourly_threshold)) .'</p>',
);
?>

It should be

<?php
$form['flood'] = array(
     '#type' => 'markup',
     '#value' => '<p>'. format_plural($print_mail_hourly_threshold,'You cannot send more than 1 message per hour. Please try again later.', 'You cannot send more than @count messages per hour. Please try again later.') . '</p>',
);
?>

ِAttached patch