updated Migration wording

migration/Jazzy.rst

@@ -203,5 +203,4 @@ Default value:
 New Plugin Container Layer
 **************************
 
-In `PR #4785 <https://github.com/ros-navigation/navigation2/pull/4785>`_ a new boolean parameter named `disable_collision_checks` was added to the `DriveOnHeading`, `BackUp` and `Spin` actions to optionally disable collision checking. This can be useful, for example, in cases where you want to move the robot even in the presence of known obstacles.
-
+In `PR #4781 <https://github.com/ros-navigation/navigation2/pull/4781>`_ a costmap layer plugin type was added to support the grouping of different costmap layers under a single costmap layer. This would allow for different isolated combinations of costmap layers to be combined under one parent costmap instead of the current implementation which would indiscriminately combine all costmap layers together.