Improve inline mail snippet rendering, possibly fixing Airmail?
Ref T10694. General improvements:
- Remove leading empty lines from context snippets.
- Remove trailing empty lines from context snippets.
- If we removed everything, render a note.
- Try using style instead of <pre>? My thinking is that maybe Airmail has weird default rules for <pre>, since that's the biggest / most obvious thing that's different about this element to me.
Test Plan: Viewed normal comments locally, faked a comment on an empty line in the middle of a lot of other empty lines.
Reviewed By: chad
Maniphest Tasks: T10694
Differential Revision: https://secure.phabricator.com/D15864