Spell "Relevance" correctly

Summary: Despite how I (and everyone else?) pronounce it, it is spelled with an "a". See PHI38.

Test Plan: Googled both spellings.

Reviewers: amckinley

Reviewed By: amckinley

Differential Revision: https://secure.phabricator.com/D18622

src/infrastructure/query/policy/PhabricatorCursorPagedPolicyAwareQuery.php

@@ -809,7 +809,7 @@ abstract class PhabricatorCursorPagedPolicyAwareQuery
     if ($this->supportsFerretEngine()) {
       $orders['relevance'] = array(
         'vector' => array('rank', 'fulltext-modified', 'id'),
-        'name' => pht('Relevence'),
+        'name' => pht('Relevance'),
       );
     }