Don't render "Comment T1#1" links on previews

Summary:
I somehow missed this, we render silly nonsense in the comment previews right
now. Don't render these links if we're rendering a preview.

Test Plan:
Looked at comment previews, less nonsense.

Reviewed By: tuomaspelkonen
Reviewers: aran, jungejason, tuomaspelkonen
CC: aran, tuomaspelkonen
Differential Revision: 388

src/applications/differential/view/revisioncomment/DifferentialRevisionCommentView.php

@@ -88,7 +88,7 @@ final class DifferentialRevisionCommentView extends AphrontView {
 
     $comment_anchor = null;
     $num = $this->commentNumber;
-    if ($num) {
+    if ($num && !$this->preview) {
       Javelin::initBehavior('phabricator-watch-anchor');
       $info[] = phutil_render_tag(
         'a',

src/applications/maniphest/view/transactiondetail/ManiphestTransactionDetailView.php

@@ -183,10 +183,9 @@ class ManiphestTransactionDetailView extends AphrontView {
     $info = array();
     $info[] = $timestamp;
 
-
     $comment_anchor = null;
     $num = $this->commentNumber;
-    if ($num) {
+    if ($num && !$this->preview) {
       Javelin::initBehavior('phabricator-watch-anchor');
       $info[] = javelin_render_tag(
         'a',