Add missing FTS broadcaster (#658)

Author: christophfroehlich

doc/controllers_index.rst

@@ -62,5 +62,6 @@ Available Broadcasters
 .. toctree::
    :titlesonly:
 
+   Force Torque Sensor Broadcaster <../force_torque_sensor_broadcaster/doc/userdoc.rst>
    Joint State Broadcaster <../joint_state_broadcaster/doc/userdoc.rst>
    Imu Sensor Broadcaster <../imu_sensor_broadcaster/doc/userdoc.rst>