Time control typeaheads.

Summary: Ref T8031, Time control typeaheads

Test Plan: Edit an event, type '3', typeahead should suggest, '3:00 AM', '3:30 AM', '3:00 PM', '3:30 PM'.

Reviewers: chad, epriestley, Blessed Reviewers

Reviewed By: epriestley, Blessed Reviewers

Subscribers: Korvin, epriestley

Maniphest Tasks: T8031

Differential Revision: https://secure.phabricator.com/D12953