Update example_substitutions_launch.py (#5766)

Fixed a typo on Line 37. 

'turtlesim_msgs/srv/spawn' -> 'turtlesim/srv/spawn'

The original was using an incorrect interface name

Signed-off-by: Shreyas Bhat <[email protected]>

Author: shreyasb032

source/Tutorials/Intermediate/Launch/launch/example_substitutions_launch.py

@@ -34,7 +34,7 @@ def generate_launch_description():
                 'ros2 service call ',
                 turtlesim_ns,
                 '/spawn ',
-                'turtlesim_msgs/srv/Spawn ',
+                'turtlesim/srv/Spawn ',
                 '"{x: 2, y: 2, theta: 0.2}"'
             ]],
             shell=True