Fix typo at calendar transaction

Summary:
* Fixed conveted => converted
Ref T11576

Test Plan: * Looked at a page, where somebody converted an AllDay Event to a normal one

Reviewers: #blessed_reviewers, epriestley

Reviewed By: #blessed_reviewers, epriestley

Subscribers: epriestley

Tags: #calendar

Maniphest Tasks: T11576

Differential Revision: https://secure.phabricator.com/D16488

src/applications/calendar/xaction/PhabricatorCalendarEventAllDayTransaction.php

@@ -24,7 +24,7 @@ final class PhabricatorCalendarEventAllDayTransaction
         $this->renderAuthor());
     } else {
       return pht(
-        '%s conveted this from an all day event.',
+        '%s converted this from an all day event.',
         $this->renderAuthor());
     }
   }