[3.13] gh-128062: Fix the font size and shortcut display of the turtledemo menu (GH-128063) (#128101)

gh-128062: Fix the font size and shortcut display of the turtledemo menu (GH-128063)

Leave the font of the menu bar the default to keep it consistent with the rest of the world. Display the shortcut keys in the right way, using the 'accelerator' option.
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(cherry picked from commit e163e8d4e1a9844b8615ef38b9917b887a377948)

Co-authored-by: Zhikang Yan <2951256653@qq.com>
Co-authored-by: Peter Bierma <zintensitydev@gmail.com>
Co-authored-by: Terry Jan Reedy <tjreedy@udel.edu>