Wordpress - Comment form placeholders

How to add placeholders to comments form?

function fedojo_update_fields($fields)
{

    $commenter = wp_get_current_commenter();
    $req = get_option('require_name_email');
    $aria_req = ($req ? " aria-required='true'" : '');

    $fields['author'] =
        '<p class="comment-form-author">
            <input required minlength="3" maxlength="30" placeholder="' . __("Your Name*", "fedojo_theme") . '" id="author" name="author" type="text" value="' . esc_attr($commenter['comment_author']) .
        '" size="30"' . $aria_req . ' />
        </p>';

    $fields['email'] =
        '<p class="comment-form-email">
            <input required placeholder="' . __("Your Email*", "fedojo_theme") . '" id="email" name="email" type="email" value="' . esc_attr($commenter['comment_author_email']) .
        '" size="30"' . $aria_req . ' />
        </p>';

    $fields['url'] =
        '<p class="comment-form-url">
            <input placeholder="' . __("Your Email*", "fedojo_theme") . '" id="url" name="url" type="url" value="' . esc_attr($commenter['comment_author_url']) .
        '" size="30" />
        </p>';

    return $fields;
}

add_filter('comment_form_default_fields', 'fedojo_update_fields');

function fedojo_comment_field($comment_field)
{

    $comment_field =
        '<p class="comment-form-comment">
            <textarea required placeholder="Enter Your Comment…" id="comment" name="comment" cols="45" rows="8" aria-required="true"></textarea>
        </p>';

    return $comment_field;
}

add_filter('comment_form_field_comment', 'fedojo_comment_field');