GH-121584: Toggle helper instead of nesting instances when using key bindings

[saucoide]

Adds a flag to check if the helper is active, interrupting it instead of opening a new instance if so

This is to stop F1 from opening multiple instances of help you need to quit individually before returning to the repl, maybe the toggling part with the sigint is not needed, but I figured paste_mode behaves that way so maybe this can too?

• Issue: gh-121584

[ghost]

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[bedevere-app[bot]]

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[bedevere-app[bot]]

Most changes to Python require a NEWS entry. Add one using the blurb_it web app or the blurb command-line tool.

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[saucoide]

@ambv i just saw that the toggle behavior for help is mentioned explicitly in the pep, any chance this will get merged or is that part going to be reworked anyway and better not to introduce more stuff?

[bedevere-app[bot]]

A Python core developer has requested some changes be made to your pull request before we can consider merging it. If you could please address their requests along with any other requests in other reviews from core developers that would be appreciated.

Once you have made the requested changes, please leave a comment on this pull request containing the phrase I have made the requested changes; please review again. I will then notify any core developers who have left a review that you're ready for them to take another look at this pull request.

[python-cla-bot[bot]]

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[saucoide]

bumping asking to take a look at this again, the latest version doesnt use signals anymore

I have made the requested changes; please review again

[bedevere-app[bot]]

Thanks for making the requested changes!

@pablogsal: please review the changes made to this pull request.