Break long words in differential two-up view

Summary: This should prevent long lines from making the code width different between files, which can be annoying. (And of course, it stops long lines from making a giant scrollbar too.)

Test Plan:
Loaded this diff in Chrome, Firefox, IE9, and IE8:

{F137505}

(That's a screenshot from Chrome, but it looks about the same in the other browsers.)

Reviewers: chad, #blessed_reviewers, epriestley

Reviewed By: #blessed_reviewers, epriestley

Subscribers: epriestley, Korvin, chad

Maniphest Tasks: T2004

Differential Revision: https://secure.phabricator.com/D8686

src/applications/diffusion/controller/DiffusionBrowseFileController.php

@@ -789,7 +789,7 @@ final class DiffusionBrowseFileController extends DiffusionBrowseController {
           $anchor_text,
 
           // NOTE: See phabricator-oncopy behavior.
-          "\xE2\x80\x8B",
+          "\xE2\x81\xA0",
 
           // TODO: [HTML] Not ideal.
           phutil_safe_html(str_replace("\t", '  ', $line['data'])),