Update README.md (ros-navigation#4114)

Signed-off-by: Steve Macenski <stevenmacenski@gmail.com>

nav2_graceful_controller/README.md

@@ -1,7 +1,7 @@
 # Graceful Motion Controller
 The graceful motion controller implements a controller based on the works of Jong Jin Park in "Graceful Navigation for Mobile Robots in Dynamic and Uncertain Environments". (2016). In this implementation, a `motion_target` is set at a distance away from the robot that is exponentially stable to generate a smooth trajectory for the robot to follow.
 
-See its [Configuration Guide Page](https://navigation.ros.org/configuration/packages/configuring-graceful-motion.html) for additional parameter descriptions.
+See its [Configuration Guide Page](https://navigation.ros.org/configuration/packages/configuring-graceful-motion-controller.html) for additional parameter descriptions.
 
 ## Smooth control law
 The smooth control law is a pose-following kinematic control law that generates a smooth and confortable trajectory for the robot to follow. It is Lyapunov-based feedback control law made of three components:
@@ -39,4 +39,4 @@ The smooth control law is a pose-following kinematic control law that generates
 | `transformed_global_plan`  | `nav_msgs/Path` | The global plan transformed into the robot frame. | 
 | `local_plan`  | `nav_msgs/Path` | The local plan generated by appliyng iteratively the control law upon a set of motion targets along the global plan. | 
 | `motion_target`  | `geometry_msgs/PointStamped` | The current motion target used by the controller to compute the velocity commands. | 
-| `slowdown`  | `visualization_msgs/Marker` | A flat circle marker of radius slowdown_radius around the motion target. | 
+| `slowdown`  | `visualization_msgs/Marker` | A flat circle marker of radius slowdown_radius around the motion target. |