decimal docs: specification link and examples

[skirpichev]

• added a direct reference to a floating-point model used
• and few examples for formatted string output

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📚 Documentation preview 📚: https://cpython-previews--128698.org.readthedocs.build/

[StanFromIreland]

Everything looks good to me

[skirpichev]

@ericvsmith, refs to format/f-strings - added.

[ericvsmith]

@ericvsmith, refs to format/f-strings - added.

I think that's good. It doesn't mention str.format, but that's not so important any more and I hope that anyone who really cares about it knows that it's all based on __format__.

[skirpichev]

It doesn't mention str.format, but that's not so important

I think this will be too verbose, it's already mention the format() builtin docs, which has links to __format__ and then to str.format()

[ericvsmith]

It doesn't mention str.format, but that's not so important

I think this will be too verbose, it's already mention the format() builtin docs, which has links to __format__ and then to str.format()

Agreed.