MAGETWO-85264: Backport #4958 to 2.1 #12611

 - Merge Pull Request #12611 from slackerzz/magento2:backport-pr4958
 - Merged commits:
   1. 5158a78

Author: mzeis

app/code/Magento/Newsletter/view/frontend/templates/subscribe.phtml

@@ -8,7 +8,7 @@
 
 ?>
 <div class="block newsletter">
-    <div class="title"><strong>Newsletter</strong></div>
+    <div class="title"><strong><?= $block->escapeHtml(__('Newsletter')) ?></strong></div>
     <div class="content">
         <form class="form subscribe"
             novalidate