[3.12] gh-72284: Revise lists in IDLE doc (GH-114174) (#114175)

Tkinter is a fact, not necessarily a feature.

Reorganize editor key bindings in a logical order
and remove those that do not work, at least on Windows.

Improve shell bindings list.
(cherry picked from commit 4a32275389d94ba41f8881c32ad4b232effb1c6f)

Co-authored-by: Terry Jan Reedy <tjreedy@udel.edu>