New: Display plus icon for inline transcript button (#296)

Author: kirsty-hames

less/media.less

@@ -37,6 +37,10 @@
     .icon-tick;
   }
 
+  &__transcript-btn-inline .icon {
+    .icon-plus;
+  }
+
   &__transcript-body-inline {
     display: none;
   }