Adding new notes for messages and services

README.md

@@ -107,6 +107,10 @@ If we want to look at descriptive stats of the rate of messages published to a t
 rostopic hz /command
 ```
 
+Built messages will be located in 
+
+`./devel/lib/python3/dist-packages/<package-name>/msg/_<message-name>.py` at the root of your Catkin workspace
+
 ## Parameters and Services
 
 ### Services
@@ -160,6 +164,10 @@ name: "turtle2"
 
 Spawns a second turtle
 
+Built service definitions will be located in 
+
+`./devel/lib/python3/dist-packages/<package-name>/srv/_<service-name>.py` at the root of your Catkin workspace
+
 ### Parameters
 
 ROS provides a parameter server that you read and write values to.