Fix some HTML problems

Summary: I'm too lazy to attaching them for diffs where they were introduced.

Test Plan:
/
/D1, wrote comment with code snippet
DarkConsole
commit detail, wrote comment
task detail, wrote comment

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Korvin

Maniphest Tasks: T2432

Differential Revision: https://secure.phabricator.com/D4911

src/applications/phame/controller/post/PhamePostEditController.php

@@ -148,7 +148,7 @@ final class PhamePostEditController
         ->setValue($submit_button)
       );
 
-    $preview_panel =
+    $preview_panel = hsprintf(
       '<div class="aphront-panel-preview">
          <div class="phame-post-preview-header">
            Post Preview
@@ -158,7 +158,7 @@ final class PhamePostEditController
              Loading preview...
            </div>
          </div>
-       </div>';
+       </div>');
 
     require_celerity_resource('phame-css');
     Javelin::initBehavior(