add comments to dummy engine

searx/engines/dummy.py

@@ -1,6 +1,14 @@
+## Dummy
+# 
+# @results     empty array
+# @stable      yes
+
+
+# do search-request
 def request(query, params):
     return params
 
 
+# get response from search-request
 def response(resp):
     return []