docs: fix code block sample for _next field

Author: phanak-sap

docs/usage/querying.rst

@@ -163,6 +163,7 @@ pair is included, where the value is a URI which identifies the next partial set
 
 
 .. code-block:: python
+
     employees = northwind.entity_sets.Employees.get_entities().select('EmployeeID,LastName').execute()
     while True:
         for employee in employees:
@@ -173,4 +174,4 @@ pair is included, where the value is a URI which identifies the next partial set
           break
 
         # We got a partial answer - continue with next page
-        employees = northwind.entity_sets.Employees.get_entities().next_url(employees.next_url).execute()
+        employees = northwind.entity_sets.Employees.get_entities().next_url(employees.next_url).execute()