Docs/Fix running-tests.md accuracy

Created by: jayeclark

Signed-off-by: Jay Clark jay@jayeclark.dev

Fixes #11548

I came across issue #11548 and added a fix to make the docs match the current reality of src/App.test.js.

docusaurus/docs/running-tests.md

@@ -81,7 +81,7 @@ it('renders without crashing', () => {
 });
 ```
 
-This test mounts a component and makes sure that it didn’t throw during rendering. Tests like this provide a lot of value with very little effort so they are great as a starting point, and this is the test you will find in `src/App.test.js`.
+This test mounts a component and makes sure that it didn’t throw during rendering. Tests like this provide a lot of value with very little effort so they are great as a starting point.
 
 When you encounter bugs caused by changing components, you will gain a deeper insight into which parts of them are worth testing in your application. This might be a good time to introduce more specific tests asserting specific expected output or behavior.
 
@@ -112,16 +112,18 @@ import '@testing-library/jest-dom';
 Here's an example of using `react-testing-library` and `jest-dom` for testing that the `<App />` component renders "Learn React".
 
 ```js
-import React from 'react';
 import { render, screen } from '@testing-library/react';
 import App from './App';
 
-it('renders welcome message', () => {
+test('renders learn react link', () => {
   render(<App />);
-  expect(screen.getByText('Learn React')).toBeInTheDocument();
+  const linkElement = screen.getByText(/learn react/i);
+  expect(linkElement).toBeInTheDocument();
 });
 ```
 
+This test is included in `src/App.test.js` as an example to get you started. Altering the content of App.js that contains the target phrase will result in a failed test, so you'll need to alter this test to match the new content of your app.
+
 Learn more about the utilities provided by `react-testing-library` to facilitate testing asynchronous interactions as well as selecting form elements from the [`react-testing-library` documentation](https://testing-library.com/react) and [examples](https://codesandbox.io/s/github/kentcdodds/react-testing-library-examples).
 
 ## Using Third Party Assertion Libraries