pedagogy: hide scroll bar at bottom of comments

core/static/core/style.scss

@@ -1970,6 +1970,7 @@ $pedagogy-white-text: #f0f0f0;
           grid-area: markdown;
 
           overflow: scroll;
+          overflow-x: hidden;
           margin-top: 0px;
           margin-right: 0px;
           padding: 10px;