I suggest the following release notes:
```
* The :meth:`Context.push() <django.template.Context.push>` method now returns
  a context manager which automatically calls :meth:`pop()
  <django.template.Context.pop>` upon exiting the ``with`` statement.
  Additionally :meth:`push() <django.template.Context.push>` now accepts
  parameters that are passed to the ``dict`` constructor used to build the new
  context level.
```

Additionally you will need to make a couple of changes in `docs/ref/templates/api.txt` for the deep linking to work; I'll comment inline on your branch.

Finally, this file will conflict with master since it already has a "Minor Feature" section, could you rebase to the latest master?