docs(caldav): fix RFC section for calendar query report

[ChristophWurst]

This seems to be a copy-paste error from

dav/lib/CalDAV/Xml/Request/CalendarMultiGetReport.php

Line 18 in 09ac4fd

* https://tools.ietf.org/html/rfc4791#section-7.9

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 97.23%. Comparing base (ed901a9) to head (b87003b).
⚠️ Report is 12 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff            @@
##             master    #1598   +/-   ##
=========================================
  Coverage     97.23%   97.23%           
  Complexity     2836     2836           
=========================================
  Files           175      175           
  Lines          9028     9028           
=========================================
  Hits           8778     8778           
  Misses          250      250           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.