add documentation for Magnetometer Broadcaster

Author: christianrauch

doc/controllers_index.rst

@@ -66,6 +66,7 @@ In the sense of ros2_control, broadcasters are still controllers using the same
    Pose Broadcaster <../pose_broadcaster/doc/userdoc.rst>
    GPS Sensor Broadcaster <../gps_sensor_broadcaster/doc/userdoc.rst>
    State Interfaces Broadcaster <../state_interfaces_broadcaster/doc/userdoc.rst>
+   Magnetometer Broadcaster <../magnetometer_broadcaster/doc/userdoc.rst>
 
 Filters
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magnetometer_broadcaster/doc/userdoc.rst

@@ -0,0 +1,24 @@
+:github_url: https://github.com/ros-controls/ros2_controllers/blob/{REPOS_FILE_BRANCH}/magnetometer_broadcaster/doc/userdoc.rst
+
+.. _magnetometer_broadcaster_userdoc:
+
+Magnetometer Broadcaster
+--------------------------------
+Broadcaster for magnetometer messages (type: ``sensor_msgs/msg/MagneticField``), using the ``semantic_components::MagneticFieldSensor``.
+
+Parameters
+^^^^^^^^^^^
+This controller uses the `generate_parameter_library <https://github.com/PickNikRobotics/generate_parameter_library>`_ to handle its parameters. The parameter `definition file located in the src folder <https://github.com/ros-controls/ros2_controllers/blob/{REPOS_FILE_BRANCH}/magnetometer_broadcaster/src/magnetometer_broadcaster_parameters.yaml>`_ contains descriptions for all the parameters used by the controller.
+
+List of parameters
+=========================
+.. generate_parameter_library_details:: ../src/magnetometer_broadcaster_parameters.yaml
+
+
+An example parameter file
+=========================
+
+An example parameter file for this controller can be found in `the test directory <https://github.com/ros-controls/ros2_controllers/blob/{REPOS_FILE_BRANCH}/magnetometer_broadcaster/test/magnetometer_broadcaster_params.yaml>`_:
+
+.. literalinclude:: ../test/magnetometer_broadcaster_params.yaml
+   :language: yaml