(Applies only to tasking programs.) Gives you the next task after
    the one currently visible (%VISIBLE_TASK). "Next" in this context
    is just an internal ordering that cycles through all the tasks.
    This lets you set up command procedures that cycle through all
    tasks.

    Example:

    DBG> WHILE %NEXT NEQ %ACTIVE DO -
    _DBG> (SET TASK %NEXT; SHOW CALLS)