Adds details to Calendar event feed titles

Summary: Closes T8340

Test Plan: Verify that calendar event feed titles have more detail that before.

Reviewers: lpriestley, Blessed Reviewers, epriestley

Reviewed By: lpriestley, Blessed Reviewers, epriestley

Subscribers: epriestley, Korvin

Maniphest Tasks: T8340

Differential Revision: https://secure.phabricator.com/D13352