Swap "Description" and "Invitees / Details" on Calendar event views

Summary:
Ref T11326. This reorders sections:

  - Description (if present)
  - Recurring event series info (if recurring)
  - Invitees (this also has custom stuff, if it exists)

Test Plan: Viewed some events, saw more sensible order.

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T11326

Differential Revision: https://secure.phabricator.com/D16671

src/applications/calendar/controller/PhabricatorCalendarEventViewController.php

@@ -72,9 +72,9 @@ final class PhabricatorCalendarEventViewController
           $comment_view,
         ))
       ->setCurtain($curtain)
-      ->addPropertySection($details_header, $details)
+      ->addPropertySection(pht('Description'), $description)
       ->addPropertySection($recurring_header, $recurring)
-      ->addPropertySection(pht('Description'), $description);
+      ->addPropertySection($details_header, $details);
 
     return $this->newPage()
       ->setTitle($page_title)