message: Update TutorialAsync.md
  Add semicolon and additional notice about expect.assertion
diff: @@ -113,7 +113,7 @@ if a Promise throws and the error is not handled, the test will fail. `expect.as
  ```js
  // Testing for async errors can be done using `catch`.
  it('tests error with promises', () => {
  - expect.assertions(1)
  + expect.assertions(1); // to be sure that `Promise` rejected and `expect` has been called once
  return user.getUserName(3)
  .catch(e => expect(e).toEqual({
  error: 'User with 3 not found.',
  @@ -122,7 +122,7 @@ it('tests error with promises', () => {
  // Or try-catch.
  it('tests error with async/await', async () => {
  - expect.assertions(1)
  + expect.assertions(1); // to be sure that `await` throws error and `expect` has been called once
  try {
  await user.getUserName(2);
  } catch (object) {
  