message: mark another argument optional
diff: @@ -556,7 +556,7 @@ export function append(parent: Node, newNode: Node) {
  insertNode(parent, parent.childNodes!.length, newNode);
  }
  -export function parse(text: string, options: parse5.ParserOptions) {
  +export function parse(text: string, options?: parse5.ParserOptions) {
  const parser = new parse5.Parser(parse5.TreeAdapters.default, options);
  return parser.parse(text);
  }
  