Clarify where the power switch must be

We definitely introduced this regulation at some point and we have
had to turn competitors away from the arena for having power switches
*inside* the robot, so being really clear about this is important.

Author: PeterJCLaw

kit/safety-regulations.md

@@ -63,7 +63,8 @@ The following procedure will be used when testing a robot:
        the XT60 connector were currently connected).
 
     8. Check that the power switch on the power board is easily
-       accessible.
+       accessible. This must be on the exterior of the robot, not
+       behind any covers and ideally on the top.
 
     9. Check that all electronics are securely fixed to the robot.