[view] write debug info into a `pre` tag

views.py

@@ -114,7 +114,9 @@
                                        children_for=children_for)
         if 'debug-es' in self._cw.form:
             import json
-            self.w(unicode(json.dumps(search._s.to_dict())))
+            self.w(u'<pre>')
+            self.w(unicode(json.dumps(search._s.to_dict(), indent=2)))
+            self.w(u'</pre>')
             self.w(u'<br/>')
         try:
             return search.execute()