Fix Maniphest and Config transaction diff rendering

Summary:
I missed this in review of D5155: `wordwrap()` returns a string, but `phutil_utf8_hard_wrap()` returns an array.

Implode the returned arrays so the stuff underneath it doesn't choke.

Test Plan: Clicked "show details" on a maniphest task description change

Reviewers: AnhNhan, kwadwon

Reviewed By: kwadwon

CC: aran

Differential Revision: https://secure.phabricator.com/D5195

src/applications/phriction/controller/PhrictionDiffController.php

@@ -49,8 +49,9 @@ final class PhrictionDiffController
     $text_r = $content_r->getContent();
 
     $text_l = phutil_utf8_hard_wrap($text_l, 80);
+    $text_l = implode("\n", $text_l);
     $text_r = phutil_utf8_hard_wrap($text_r, 80);
-
+    $text_r = implode("\n", $text_r);
 
     $engine = new PhabricatorDifferenceEngine();
     $changeset = $engine->generateChangesetFromFileContent($text_l, $text_r);