add missing word

"if the property" doesn't seem right to me.

Author: tacman

components/workflow.rst

@@ -75,7 +75,7 @@ Here's an example of using the workflow defined above::
 Initialization
 --------------
 
-If the property of your object is ``null`` and you want to set it with the
+If the marking property of your object is ``null`` and you want to set it with the
 ``initial_marking`` from the configuration, you can call the ``getMarking()``
 method to initialize the object property::