Distinguish between ported-forward and ported-backward comments
Summary:
Ref T7447. This might be overkill, but I want to over-explain things until we have more confidence that this is rarely confusing.
NOTE: I'm playing it a bit fast and loose with setIsGhost() (passing a dictionary) because making API changes requires changing the interface and Diffusion, which is a pain. I'll clean this up at the end once the interface is more final. This is well-contained for now.
Test Plan:
- Viewed "base vs 2" in a diff with 3 diffs, saw some "older comments" and some "newer comments".
- Hovered the tags for an explanation of comment spookiness.
{F377703}
Reviewers: btrahan
Reviewed By: btrahan
Subscribers: epriestley
Maniphest Tasks: T7447
Differential Revision: https://secure.phabricator.com/D12490