Help endpoint does not make sense for the rest api server.

therefore, remove the TODO.

freqtrade/rpc/api_server.py

@@ -222,9 +222,6 @@ class ApiServer(RPC):
         self.app.add_url_rule(f'{BASE_URI}/forcesell', 'forcesell', view_func=self._forcesell,
                               methods=['POST'])
 
-        # TODO: Implement the following
-        # help (?)
-
     @require_login
     def page_not_found(self, error):
         """