clarify the compile-time composition behavior. (#4088) (#4090)

(cherry picked from commit 6bb52ea)

Co-authored-by: VictorLee <[email protected]>

source/Tutorials/Intermediate/Composition.rst

@@ -133,11 +133,11 @@ In the second shell (see `server <https://github.com/ros2/demos/blob/{REPOS_FILE
 
 In this case the client sends a request to the server, the server processes the request and replies with a response, and the client prints the received response.
 
-Compile-time composition using ROS services
-^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+Compile-time composition with hardcoded nodes
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-This demo shows that the same shared libraries can be reused to compile a single executable running multiple components.
-The executable contains all four components from above: talker and listener as well as server and client.
+This demo shows that the same shared libraries can be reused to compile a single executable running multiple components without using ROS interfaces.
+The executable contains all four components from above: talker and listener as well as server and client, which is hardcoded in the main function.
 
 In the shell call (see `source code <https://github.com/ros2/demos/blob/{REPOS_FILE_BRANCH}/composition/src/manual_composition.cpp>`__):