Feature Request: Mark 'todo' tests as 'skipped'

Currently, if you have a todo test:

```ts
it.todo('test not written yet')
```

It shows up as as success in the XML report:

```xml
<testcase classname="" name="test not written yet" time="0">
</testcase>
```

It feels like these should show the same as `it.skip` tests, skipped in the XML (since I don't believe there's any way of marking something as todo/pending in the XML schema)