re-classing response save button to match its purpose better

apps/openassessment/templates/openassessmentblock/response/oa_response.html

@@ -41,7 +41,7 @@
 
                 <ul class="list list--actions response__submission__actions">
                     <li class="list--actions__item">
-                        <button type="submit" id="submission__submit" class="action action--submit submission__submit">Save Your Progress</button>
+                        <button type="submit" id="submission__save" class="action action--save submission__save">Save Your Progress</button>
                         <span class="tip">you may continue to work on your response until you submit</span>
                     </li>
                 </ul>

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

@@ -479,7 +479,7 @@
         }
       }
 
-      .action--submit {
+      .action--save {
         @extend %btn--secondary;
         @extend %action-delta;
         display: block;