Pointing out namespace in docs (#2874)

docs/advanced/functions.rst

@@ -50,7 +50,7 @@ implied transfer of ownership, i.e.:
 
 
 .. code-block:: cpp
 .. code-block:: cpp
 
 
-    m.def("get_data", &get_data, return_value_policy::reference);
+    m.def("get_data", &get_data, py::return_value_policy::reference);
 
 
 On the other hand, this is not the right policy for many other situations,
 On the other hand, this is not the right policy for many other situations,
 where ignoring ownership could lead to resource leaks.
 where ignoring ownership could lead to resource leaks.