[3.11] gh-82006: IDLE doc improvements (GH-94349) by miss-islington · Pull Request #94357 · python/cpython

0. Update text start and stop conditions.
1. Title-case sections but not subsections.
2. Edit Shell Window sections: title, execute, restart.
(cherry picked from commit e6391e0)

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