Updates key format

This PR changes the format of the keys in the output like so:

```javascript
[
  'header': '/headers/header1.html',
  'footer': '/footers/footer1.html',
  'checkout/header': '/headers/header9.html',
  'checkout/foo/bool': false,
  'checkout/foo/num': 123,
  'checkout/foo/arr': 'NOT SUPPORTED'
]
```