Add an extension for a "Note to Reviewers" field on review requests.

Review Request #6026 — Created June 23, 2014 and submitted — Latest diff uploaded


This extension adds a "Note to Reviewers" field below "Testing Done,"
which developers can use to give instructions on what to focus on or
to pre-answer questions that may be asked, without lumping those into
the description of the change.

This field is saved and published along with the draft.

While useful, it largely functions as a demo for how to add a simple

Installed the extension and saved some text, and published it.

Tested with Markdown.

This is actually the extension I used when I was testing some of the custom
field hooks initially.