[3.9] bpo-42560: rewrite of Tkinter docs "life preserver" (GH-27842)

[miss-islington]

Co-authored-by: Łukasz Langa lukasz@langa.pl
(cherry picked from commit 08830a4)

Co-authored-by: Mark Roseman mark@markroseman.com

https://bugs.python.org/issue42560

[miss-islington]

@roseman and @ambv: Status check is done, and it's a success ✅ .

[miss-islington]

@roseman and @ambv: Status check is done, and it's a success ✅ .

[miss-islington]

@roseman and @ambv: Status check is done, and it's a success ✅ .

[miss-islington]

@roseman and @ambv: Status check is done, and it's a success ✅ .

[miss-islington]

@roseman and @ambv: Status check is done, and it's a failure ❌ .

[terryjreedy]

Given that there was no merge conflict, why was this closed? If it it not going to be merged, the label on #27842 should be removed. I am asking in particular because bpo-45029 is about the old example, run in 3.9, that this replaces. So backporting the replacement seems like a good idea.

[E-Paine]

@ambv Can we reopen this for merge? As Terry said, bpo-45029 is related to this, so IMO it would be nice to get this in the 3.9 docs.