Merge pull request #2830 from MarcGuay/patch-23

Update part4b.md

Author: mluukkai

src/content/4/en/part4b.md

@@ -164,7 +164,7 @@ In principle, the test could also have been defined as a string
 
 The problem here, however, is that when using a string, the value of the header must be exactly the same. For the regex we defined, it is acceptable that the header <i>contains</i> the string in question. The actual value of the header is <i>application/json; charset=utf-8</i>, i.e. it also contains information about character encoding. However, our test is not interested in this and therefore it is better to define the test as a regex instead of an exact string.
 
-The test contains some details that we will explore [a bit later on](/en/part4/testing_the_backend#async-await). The arrow function that defines the test is preceded by the <i>async</i> keyword and the method call for the <i>api</i> object is preceded by the <i>await</i> keyword. We will write a few tests and then take a closer look at this async/await magic. Do not concern yourself with them for now, just be assured that the example tests work correctly. The async/await syntax is related to the fact that making a request to the API is an <i>asynchronous</i> operation. The [Async/await syntax](https://jestjs.io/docs/asynchronous) can be used for writing asynchronous code with the appearance of synchronous code.
+The test contains some details that we will explore [a bit later on](/en/part4/testing_the_backend#async-await). The arrow function that defines the test is preceded by the <i>async</i> keyword and the method call for the <i>api</i> object is preceded by the <i>await</i> keyword. We will write a few tests and then take a closer look at this async/await magic. Do not concern yourself with them for now, just be assured that the example tests work correctly. The async/await syntax is related to the fact that making a request to the API is an <i>asynchronous</i> operation. The [async/await syntax](https://jestjs.io/docs/asynchronous) can be used for writing asynchronous code with the appearance of synchronous code.
 
 Once all the tests (there is currently only one) have finished running we have to close the database connection used by Mongoose. This can be easily achieved with the [afterAll](https://jestjs.io/docs/api#afterallfn-timeout) method: