Fix reticle with edit inline comment

Test Plan:

• Hover left comment on diff of diff.
• Hover right comment on diff of diff.
• Hover inline comment preview.
• Hover inline comment edit.

Reviewers: epriestley

Reviewed By: epriestley

CC: aran

Maniphest Tasks: T1076

Differential Revision: https://secure.phabricator.com/D2213