PEP 489: Fix syntax highlighting

[hugovk]

Most of the code blocks are C, so set that as the document highlight, and use Python on blocks where needed.

Also add inline code formatting.

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📚 Documentation preview 📚: https://pep-previews--4456.org.readthedocs.build/

[encukou]

Umm... Does this historical document really need updating to current publication standards?

[hugovk]

No, It's not absolutely needed, but would improve readability: the doc still exists and I was referred to it via python-pillow/Pillow#8983. I guess I should have looked up the real docs instead :)

Anyway, I can ditch the second commit if it makes it easier to review, and/or add the canonical docs banner to the top (to https://docs.python.org/3/c-api/module.html#multi-phase-initialization ?) to make it clearer this is history?

[AA-Turner]

I think this is fine to change, it's editorial/style rather than the content, which is the class of changes we tend to take more exception to.

A

[encukou]

add the canonical docs banner to the top

That's the thing to do :)

It would be nice to get python/cpython#135126 in before that, and link to its new extension-modules.rst. Could I ask for a review there?

[encukou]

Now merged. Would a canonical docs banner like this be appropriate?

.. canonical-doc:: :ref:`python:initializing-modules`.
                   For Python 3.14+, see :ref:`py3.14:extension-modules`
                   and :ref:`py3.14:pymoduledef`

[hugovk]

Thanks, added!

I would like to keep at least the first commit, as while this PEP is indeed historical, it is still read, and we even link to it a dozen times from the CPython docs.