[Documentation Issue] Datastore docs don't seem to reference client pattern?

[jgeewax]

Page Name: datastore-keys
Release: 0.8.0

Looks like a lot of our snippet documentation is out of date since the client pattern changes. Can we go through and "assume" there's a client at the start of each method, and write docs that fit there? Or re-do the snippets so that they work?

/cc @dhermes : I know we have a separate issue for testing the snippets as doctests (and it was stalled due to ... mocking concerns among other things). Figure this is worth a look.

[dhermes]

For posterity, the referred to issue is #212

[dhermes]

Also relevant is the discussion in #1141.

[dhermes]

I think this was settled by #1352, but am double-checking.