gh-143331: Schedule to remove format "N" for Decimal

[donbarbos]

• Issue: gh-143331

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📚 Documentation preview 📚: https://cpython-previews--143372.org.readthedocs.build/

[donbarbos]

Shouldn't this also be added to 3.13 and 3.14 whatsnew entries?

[hugovk]

For visibility, let's also mention the removal version in the deprecation warning:

https://github.com/python/cpython/blob/be0074f1abd9079e78181ae57a1a68630ef05404/Modules/_decimal/_decimal.c#L3597-L3598

[miss-islington-app[bot]]

Thanks @donbarbos for the PR, and @hugovk for merging it 🌮🎉.. I'm working now to backport this PR to: 3.13, 3.14. 🐍🍒⛏🤖

[miss-islington-app[bot]]

Sorry, @donbarbos and @hugovk, I could not cleanly backport this to 3.14 due to a conflict. Please backport using cherry_picker on command line.

cherry_picker dd750b348501247d458ea8d454213d4959a8f8b9 3.14

[miss-islington-app[bot]]

Sorry, @donbarbos and @hugovk, I could not cleanly backport this to 3.13 due to a conflict. Please backport using cherry_picker on command line.

cherry_picker dd750b348501247d458ea8d454213d4959a8f8b9 3.13

[bedevere-app[bot]]

GH-143476 is a backport of this pull request to the 3.14 branch.

[bedevere-app[bot]]

GH-143477 is a backport of this pull request to the 3.13 branch.