Suggest adding exec_dependency on ros2launch for packages with launch…

… files

Signed-off-by: Christophe Bedard <[email protected]>

source/Guides/Launch-file-different-formats.rst

@@ -255,6 +255,17 @@ or run the file directly by specifying the path to the launch file
 
   ros2 launch <path_to_launch_file>
 
+.. note::
+
+  For packages with launch files, it is a good idea to add an ``exec_depend`` dependency on the ``ros2launch`` package in your package's ``package.xml``:
+
+  .. code-block:: xml
+
+    <exec_depend>ros2launch</exec_depend>
+
+  This helps make sure that the ``ros2 launch`` command is available after building your package.
+  It also ensures that all launch file formats are recognized.
+
 Setting arguments
 ^^^^^^^^^^^^^^^^^