Summary:
Ref T11809. This came out of Facebook many years ago for computing the number of business days that revisions had been stale.
We removed the little staleness marker a few months ago and haven't seen complaints about it.
If we did holidays now it would make sense to integrate them more directly with Calendar as real events, but I have no plans to pursue this anytime soon. It's easy enough to add the federal holidays manually (~5 minutes of work per year?) if you want them, and they're commentable/editable and you can add local holidays if you're not in the US.
Test Plan:
- Ran `bin/storage upgrade -f`.
- Grepped for `CalendarHoliday`.
Reviewers: chad
Reviewed By: chad
Maniphest Tasks: T11809
Differential Revision: https://secure.phabricator.com/D16788
