What's new for 0.11.0 release.

This PR updates the `what's new` for the impending 0.11.0 release.

- [ ] Rebase with upstream master.
- [ ] Review latest commits for inclusion.
Apparently numpydoc is required for building the docs. Hence this shouldn't have been giving errors.

In which case... if the built documentation looks consistent across both the numpydoc and non-numpydoc styles then I wouldn't bother making these changes. If it looks inconsistent then I'm :+1: for what you've done here.