Fix Markdown rendering issues with the new field support.
The new field support didn't convert new review requests to Markdown,

yet it would escape the text. The result was seeing an uploaded

description in escaped Markdown.
We want to always render the built-in Description and Testing Done

fields in Markdown. To do this, there's now an always_render_markdown

attribute on the field that ensures the result will always be Markdown.

This will still factor in whether the source text needs to be escaped or

not.

Posted a change locally that had Markdown formatting in the Description.

Saw that it rendered to Markdown but escaped the text, as it did before the

new field work went in.
Updated the Description field and added my own Markdown formatting. It rendered

as Markdown.