add copy code button

app/templates/threads/thread.html

@@ -83,7 +83,7 @@
   </span>
 </div>
 {%- if is_logged_in() and get_active_user().can_post_to_thread_or_topic(thread) -%}
-<form action="{{url_for('threads.reply', thread_id=thread.id)}}" method="POST" class="plank post-edit-form">
+<form action="{{url_for('threads.reply', thread_id=thread.id)}}" method="POST" class="plank post-edit-form" data-listen="submit" data-r="clearThreadDraft" data-s="clearThreadDraft">
   <h2 class="info">Reply to "{{thread.title}}"</h2>
   {{- babycode_editor_component() -}}
   <span>