Fix-up class name duplication in PR GH-7807. Combined effect is that
module calltips and its class CallTips are now calltip and Calltip.
In module calltip_w class CallTip is now CalltipWindow.
(cherry picked from commit 9af1836664)
Co-authored-by: Terry Jan Reedy <tjreedy@udel.edu>
Improve consistency and appearance. Module idlelib.calltips is now calltip.
Class idlelib.calltip_w.CallTip is now Calltip.
(cherry picked from commit 06e2029dfa)
Co-authored-by: Terry Jan Reedy <tjreedy@udel.edu>