app/Template/comment/edit.php

<div class="page-header">
    <h2><?= t('Edit a comment') ?></h2>
</div>

<form method="post" action="<?= $this->url->href('CommentController', 'update', array('task_id' => $task['id'], 'comment_id' => $comment['id'])) ?>" autocomplete="off">
    <?= $this->form->csrf() ?>

    <?= $this->form->textEditor('comment', $values, $errors, array('autofocus' => true, 'required' => true, 'aria-label' => t('Comment'))) ?>

    <?= $this->modal->submitButtons() ?>
</form>