Calendar tooltips should always show start and end time of events.
Summary: Closes T8191, Calendar tooltips should always show start and end time of events.
Test Plan: Open month view, hover over, All day events, multi-day all day events, multi-day non-all-day events, and regular events. Tooltips should be "All day", "All day, <start> - <end>", "<start>-<end>", and "<start>-<end>", respectively.
Reviewers: epriestley, Blessed Reviewers, chad
Reviewed By: epriestley, Blessed Reviewers
Subscribers: Korvin, epriestley
Maniphest Tasks: T8191
Differential Revision: https://secure.phabricator.com/D12846