Document QueryIterator class?

[snarfed]

Hi all! I noticed recently that the QueryIterator class (in _datastore_query.py) is missing from the docs. I'm guessing that's not intentional? It's mentioned in the nitpick config in Sphinx's conf.py, which I expect means it was included in the docs at some point?

python-ndb/docs/conf.py

Line 45 in 7fd3ed3

("py:class", "QueryIterator"),

Any chance you could add it? Thanks in advance!