[3.11] gh-102327: Extend docs for "url" and "headers" parameters to HTTPConnection.request()

gh-102327: Extend docs for "url" and "headers" parameters to HTTPConnection.request()

Added example on how to use the HTTPConnection object for making GET request.

Original issue: https://github.com/python/cpython/issues/102327

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(cherry picked from commit 7ba6288feb961fcd60a29415c6371d2d3eb80bec)

Co-authored-by: David Foster <david@dafoster.net>
Co-authored-by: Éric <earaujo@caravan.coop>