Fix ROS Index link for realtime_tools (#473) (#475)

(cherry picked from commit 5b23df6)

Co-authored-by: Felix Exner (fexner) <[email protected]>

Author: mergify[bot]

doc/api_list/api_list.rst

@@ -156,4 +156,4 @@ realtime_tools
      - ROS Index
    * - control_msgs
      - `API <http://docs.ros.org/en/{DISTRO}/p/realtime_tools/>`__
-     - `ROS Index <https://index.ros.org/p/velocity_controllers/>`__
+     - `ROS Index <https://index.ros.org/p/realtime_tools/>`__