Landmarks note (#1242)
Landmarks note (#1242)

Added a note to point out that even if all the SLAM options are set for a 2D SLAM the landmarks will remain 3D objects.
googlecartographer/cartographer_ros,cartographer-project/cartographer_ros,cartographer-project/cartographer_ros,googlecartographer/cartographer_ros,wohe/cartographer_ros,wohe/cartographer_ros,wohe/cartographer_ros,googlecartographer/cartographer_ros,cartographer-project/cartographer_ros