Improve documentation for BaseReviewResource.update_review().

Review Request #9304 — Created Oct. 21, 2017 and submitted — Latest diff uploaded

Information

Review Board
release-3.0.x
0f2cb03...

Reviewers

BaseReviewResource.update_review() takes several important arguments,
which weren't previously documented. This is a simple change that
documents the function a bit better, adding information on the arguments
and return type.

Unit tests passed.