Document the calendar, and bring the rest up to 4.0
New Calendar page: what it is, how an administrator enables it, how a user
connects a server, what each Test result means and which URL to use for
Nextcloud, ownCloud, Radicale and Baikal. It also states plainly what is not
supported yet, since repeating events being read only will otherwise read as a
bug.
Admin manual gains a calendar section in Config, all thirteen settings,
including why max_range_days and max_occurrences exist: expanding a recurring
event is unbounded work in principle, so both the window and the count per
event need a ceiling. The Contacts menu gains the two new recipient limits.
Home lists what 4.0 added rather than stopping at 3.2: calendar, bulk contact
operations, vector icons, editor tables and the three DAV fixes. Nextcloud
support corrected to 26 through 35.
Size tables remeasured on 4.0.1 rather than 3.2.5, with calendar.js and
calendar.css added and a note that neither the calendar nor the Sieve editor
counts towards what a browser fetches at startup. The claim that the editor
still cannot do tables is gone, since it can since 4.0.