Coverage Testing

Towards the end of this section where it's talking about `istanbul` (not constantinople):
https://react-v9.holt.courses/lessons/testing/browser-tests

The `coverage` section looks like this:
```
coverage: {
provider: "istanbul"
reporter: ["text", "json", "html"],
},
```

There is a missing comma after `istanbul`. Should be:
```
coverage: {
provider: "istanbul",
reporter: ["text", "json", "html"],
},
```

Open the browser-tests lesson at https://react-v9.holt.courses/lessons/testing/browser-tests and locate the coverage section discussing istanbul. Correct the missing comma after "istanbul" in the configuration snippet, then verify the displayed example matches the corrected version in the issue.

Written by the indexing model from the issue text.