Docs: Add note to ¨Configure Python" section about sysconfig module

[manuels]

There is no information about how to retrieve compile-time configuration options of the interpreter on the "Configure Python" documentation page, so this MR adds a sentence about the sysconfig module.

(I assume this is a trivial change, so no Github issue is required first)

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:books: Documentation preview :books:: https://cpython-previews--112360.org.readthedocs.build/

[ghost]

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