Doc build leaves behind a test.json file
I think from https://github.com/pandas-dev/pandas/blob/aa59954a217c8f856bb0980265520d37b85a80af/doc/source/whatsnew/v0.23.0.txt#L220.

It should be removed in a hidden ipython block afterwards.

```
.. ipython:: python
   :suppress:

   import os
   os.remove('test.json')
```