DisplayProperties::isBoldTag

protected function isBoldTag($tagName)
{
	$boldTagNames = [
		'b' => true, 'mark' => true, 'em' => true, 'strong' => true, 'h1' => true, 'h2' => true, 'h3' => true,
		'h4' => true, 'h5' => true, 'h6' => true,
	];

	return isset($boldTagNames[mb_strtolower($tagName)]);
}