Add a line break after quote insertion

boards/static/js/thread.js

@@ -38,7 +38,7 b' function addQuickReply(postId) {'
     var textToAdd = '>>' + postId + '\n\n';
     var selection = window.getSelection().toString();
     if (selection.length > 0) {
-        textToAdd += '> ' + selection;
+        textToAdd += '> ' + selection + '\n\n';
     }
 
     var textAreaId = 'textarea';