DotCodes

I would also like to add a text that appears which tells you that special characters aren’t allowed.

You can try adding in functions.php from theme folder right at bottom before closing the php tag ?> the following code :

function wp_move_comment_field_to_bottom( $fields ) {
$comment_field = $fields['comment'];
unset( $fields['comment'] );
$fields['comment'] = $comment_field;

return $fields;
}
add_filter( 'comment_form_fields', '_move_comment_field_to_bottom' );