gh-75510: Edit idlelib entry in doc (GH-95869)

Make section instead of subsection and revise sentence.
(cherry picked from commit 9af4aed73af0accffd26176c09aa263b68c8ca5d)

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

Miss Islington (bot) committed 3y ago

759227f7e9a50ad7efd9342cfafc294655f01599

Parent: fe5cc63

Committed by GitHub <noreply@github.com> on 8/11/2022, 3:03:01 AM