This change updates the rbchecklist extension for Review Board 5.0.x and

Django 3.2. This extension was also broken in a few ways, and I've fixed

up the things that were causing it to break (some problems with error

handling on the JS side, and a missing HTML element that was causing the

settings page to show poorly).
I'd really like to start over on this extension--what we have is both

under-featured and over-complex, and the visual design is highly

lacking. For now, this change gets things limping along again.

Installed and activated the extension. Was able to use the features

successfully.