Render Remarkup in emails
Summary: Ref T992. I noticed that ManiphestTask mail doesn't render Remarkup properly (instead, it renders Remarkup literally). I think this is because the code calls addTextSection() rather than addRemarkupSection().
Test Plan: Created a new Maniphest Task and saw Remarkup in the generated self-email (inspect the email contents with ./bin/mail show-outbound). I didn't test the other affected applications.
Reviewers: epriestley, Blessed Reviewers
Reviewed By: epriestley, Blessed Reviewers
Maniphest Tasks: T992
Differential Revision: https://secure.phabricator.com/D14511