[3.10] gh-82006: IDLE doc improvements (GH-94349)

[miss-islington]

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

• Issue: IDLE doc improvements #82006

[miss-islington]

Status check is done, and it's a success ✅ .

[miss-islington]

@terryjreedy: Status check is done, and it's a success ❌ .

[miss-islington]

@terryjreedy: Status check is done, and it's a success ❌ .

[terryjreedy]

@ezio-melotti @JulienPalard The Docs/Docs test failed with

Warning, treated as error:
[library/idle:597] "`" found in "Lines containing`’RESTART’` mean that the user execution process has been"
make[1]: *** [Makefile:51: build] Error 2
make: *** [Makefile:115: suspicious] Error 1
make[1]: Leaving directory '/home/runner/work/cpython/cpython/Doc'
Suspicious check complete; look for any errors in the above output or in build/suspicious/suspicious.csv.  If all issues are false positives, append that file to tools/susp-ignored.csv.
make: Leaving directory '/home/runner/work/cpython/cpython/Doc'
Error: Process completed with exit code 2.

(I noticed the missing ' '.) This same test passed for main and 3.11, and for main, the resulting .html looks OK.
Why fail here?

Since this is not required, I could commit anyway. Any problem? Or ask someone else?

[miss-islington]

@terryjreedy: Status check is done, and it's a success ❌ .

[miss-islington]

@terryjreedy: Status check is done, and it's a success ❌ .

[miss-islington]

@terryjreedy: Status check is done, and it's a success ❌ .

[miss-islington]

@terryjreedy: Status check is done, and it's a success ❌ .

[miss-islington]

@terryjreedy: Status check is done, and it's a success ❌ .

[terryjreedy]

@JulienPalard @ambv Thank you both for the fixes which result in all 3 versions looking the same.