Update launch file to use output="both" (#357)

Author: AndyZe

doc/tutorials/quickstart_in_rviz/launch/demo.launch.py

@@ -175,10 +175,7 @@ def generate_launch_description():
         package="controller_manager",
         executable="ros2_control_node",
         parameters=[robot_description, ros2_controllers_path],
-        output={
-            "stdout": "screen",
-            "stderr": "screen",
-        },
+        output="both",
     )
 
     # Load controllers