[3.13] gh-128562: Fix generation of the tkinter widget names (GH-128604) (GH-128791)

There were possible conflicts if the widget class name ends with a digit.
(cherry picked from commit da8825ea95a7096bb4f933d33b212a94ade10f6e)

Co-authored-by: Zhikang Yan <2951256653@qq.com>