Add a "Description" header to the repository view for consistency

Summary: We don't have a section header on `/diffusion/X/` for descriptions right now. Add one to improve consistency.

Test Plan: Looked at a repository.

Reviewers: chad, btrahan

Reviewed By: chad

CC: aran

Differential Revision: https://secure.phabricator.com/D7449

src/applications/diffusion/controller/DiffusionRepositoryController.php

@@ -185,6 +185,7 @@ final class DiffusionRepositoryController extends DiffusionController {
         $repository,
         'description',
         $user);
+      $view->addSectionHeader(pht('Description'));
       $view->addTextContent($description);
     }