For readers -- fix the doc links on python.org

The documentation tab on python.org is not very friendly:

Several links take you to this useless interstitial page: https://www.python.org/doc/ -- instead the tab should take you directly to https://docs.python.org/3/, or at the very least it should have a bold yellow button that takes you there (rather than a gray one).

Some other materials are seriously outdated or limited; the A/V link goes to a page with mostly outdated podcasts, for example (the list of recent PyCon talks is at the bottom). The Beginners link goes to a wiki page. Etc., etc.

• Link to discussion about the proposal (Discourse or GitHub): not yet

See also: https://docs.google.com/presentation/d/1ujDv8wViPvAMFAtYCRxSKh-CMUlbjcfVYitsqEI2Ios/edit#slide=id.p

Inizia esaminando la scheda della documentazione e i link descritti in questa issue, in particolare /doc/ e https://docs.python.org/3/. Esamina la presentazione collegata e le destinazioni A/V e Beginners. Il lavoro è completato quando la scheda porta direttamente alla documentazione corrente e i materiali identificati come obsoleti o limitati hanno link sostitutivi concordati.