adding collapse/expand toggle to assessment feedback form UI

apps/openassessment/templates/openassessmentblock/grade/oa_grade_complete.html

@@ -138,7 +138,8 @@
                     </ol>
                 </article>
 
-                <form id="submission__feedback" class="submission__feedback  ui-toggle-visibility" method="post">
+                <form id="submission__feedback" class="submission__feedback ui-toggle-visibility" method="post">
+                    <i class="ico icon-caret-right"></i>
                     <h3 class="submission__feedback__title ui-toggle-visibility__control">Give Feedback On Peer Evaluations</h3>
 
                     <div class="submission__feedback__content {{ has_submitted_feedback|yesno:"is--submitted," }}">

apps/openassessment/xblock/static/sass/oa/views/_oa-base.scss

@@ -1123,7 +1123,11 @@
     color: $heading-secondary-color;
   }
 
-  .submission__feedback__content {
+  .submission__feeedback__title__copy {
+    margin-left: ($baseline-h/4);
+  }
+
+  .submission__feeedback__content {
     @extend %ui-subsection-content;
     margin-bottom: $baseline-v;
   }