add renderValue() in transactions

Summary: fix T11290.

Test Plan: Paste language type, view in web and in emails (It uses quotes in HTML emails, which I think is something else).

Reviewers: epriestley, chad, Blessed Reviewers

Reviewed By: chad, Blessed Reviewers

Subscribers: Korvin

Maniphest Tasks: T11290

Differential Revision: https://secure.phabricator.com/D16252