Use a less-esoteric spelling of "capabilities" in several places

Summary: This spelling can definitely feel a little overplayed at times, but I still think it's a gold standard in spellings of "capabilities".

Test Plan: Felt old and uncool.

Reviewers: chad

Reviewed By: chad

Differential Revision: https://secure.phabricator.com/D18215

src/applications/policy/controller/PhabricatorPolicyExplainController.php

@@ -253,7 +253,7 @@ final class PhabricatorPolicyExplainController
       ->appendParagraph(
         pht(
           'To access this object, users must have first have access '.
-          'capabilties on these other objects:'))
+          'capabilities on these other objects:'))
       ->appendList($items);
   }