fix cd command (#825)

workspace name was inconsistent with others.

Author: Alxkory

doc/tutorials/getting_started/getting_started.rst

@@ -46,7 +46,7 @@ Download Source Code of MoveIt and the Tutorials
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 Move into your Colcon workspace and pull the MoveIt tutorials source: ::
 
-  cd ~/ws_moveit/src
+  cd ~/ws_moveit2/src
   git clone -b humble https://github.com/ros-planning/moveit2_tutorials
 
 Next we will download the source code for the rest of MoveIt: ::