Makes rviz trajectory visualization topic relative (#2835)

This commit makes the trajectory visualization topic relative. This was
done to make sure that it respects the namespaces that are set in
launch files.

Co-authored-by: Felix von Drigalski <FvDrigalski@gmail.com>
Co-authored-by: Michael Görner <me@v4hn.de>

MIGRATION.md

@@ -26,6 +26,7 @@ API changes in MoveIt releases
 - The joint states of `passive` joints must be published in ROS and the CurrentStateMonitor will now wait for them as well. Their semantics dictate that they cannot be actively controlled, but they must be known to use the full robot state in collision checks. (https://github.com/ros-planning/moveit/pull/2663)
 - Removed deprecated header `moveit/macros/deprecation.h`. Use `[[deprecated]]` instead.
 - All uses of `MOVEIT_CLASS_FORWARD` et. al. must now be followed by a semicolon for consistency (and to get -pedantic builds to pass for the codebase).
+- In case you start RViz in a namespace, the default topic for the trajectory visualization display now uses the relative instead of the absolute namespace (i.e. `<ns>/move_group/display_planned_path` instead of `/move_group/display_planned_path`).
 
 ## ROS Melodic
 

moveit_ros/visualization/rviz_plugin_render_tools/src/trajectory_visualization.cpp

@@ -68,7 +68,7 @@ TrajectoryVisualization::TrajectoryVisualization(rviz::Property* widget, rviz::D
   , trajectory_slider_dock_panel_(nullptr)
 {
   trajectory_topic_property_ =
-      new rviz::RosTopicProperty("Trajectory Topic", "/move_group/display_planned_path",
+      new rviz::RosTopicProperty("Trajectory Topic", "move_group/display_planned_path",
                                  ros::message_traits::datatype<moveit_msgs::DisplayTrajectory>(),
                                  "The topic on which the moveit_msgs::DisplayTrajectory messages are received", widget,
                                  SLOT(changedTrajectoryTopic()), this);