appy new class name

src/server/views/layout-growi/widget/comments.html

@@ -1,6 +1,6 @@
 <div class="main-container page-comments-row row hidden-print">
 
-  <div class="page-comments col-lg-7 col-md-9">
+  <div class="page-comments col-xl-7 col-lg-9">
 
     <h4 class="my-2"><i class="icon-fw icon-bubbles"></i> Comments</h4>