studio - syncing cheatsheet language with new class name for heading 1

cms/templates/widgets/problem-edit.html

@@ -34,7 +34,7 @@
     <article class="simple-editor-cheatsheet">
         <div class="cheatsheet-wrapper">
             <div class="row">
-                <h6>Header</h6>
+                <h6>Heading 1</h6>
                 <div class="col sample header">
                     <img src="/static/img/header-example.png" />
                 </div>