[moveit_commander/robot.py] Fill in in-code document where missing.
[moveit_commander/robot.py] Fill in in-code document where missing.

davetcoleman/moveit,davetcoleman/moveit,ros-planning/moveit,v4hn/moveit,davetcoleman/moveit,v4hn/moveit,ros-planning/moveit,v4hn/moveit,ros-planning/moveit,ros-planning/moveit,davetcoleman/moveit,v4hn/moveit,ros-planning/moveit