Work on ROS2.

README.md

@@ -305,8 +305,9 @@ class InAirGoalExecutorFactory(ExecutorFactory):
             print(exc)
         return res
 ```
+```
 
-How expanding works:
+How expansion works:
 
     - There is a tst_expansion node that have a service TSTExpandTree ("tst_expand_tree"). The tree is in JSON format.
     - All running executor factories have a service call that can do expansion if needed.