R1:fda83094ac59

Restore missing behavior for Differential keyboard navigation

Summary: Fixes T12086. This got dropped by accident while cleaning up haunting.

Test Plan: Loaed a revision, hit "?", hit n/j/p/etc

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T12086

Differential Revision: https://secure.phabricator.com/D17166