GeezerVison

In #76773 , I compiled a detailed list of places where currently or (then-)to-be-unsupported Windows versions were referred to in the context of being current, with a focus on documentation. Unfortunately, as the issue became mired for a time in debates about whether and when it was necessary to drop Windows <8.1 support, I was never able to follow up and update them.

Support for Windows <8.1 was broken in PR #18231 to fix issue #83582 (CVE-2020-8315), dropped officially (albeit rather unceremoniously, with only a short news entry and without documentation updates) in @zooba 's PR #21656 to resolve issue #85584 and clarified a bit at least in the "Using Python on Windows" document in PR #23603 addressing issue #42523 . However, it appears that besides that, few of the others enumerated there were actually updated.

Therefore, this PR updates them, as well as a handful of other mentions I found in the process. In particular, it:

• Corrects statements of the supported Windows and MSVC versions to accurately reflect this
• Elides mentions of long-obsolete/unsupported Windows versions, compilers and distributions
• Revises a few other related bits in the documentation that had drifted out of date.
• Fixes numerous broken and out of date links in the above Windows-related sections
• Opportunistically updates references to long-EoL Python versions where already modifying nearby content

All of the changes should be backport-safe since the removed/updated portions are mostly long-obsolete and support for Windows <8.1 was dropped in Python 3.9, the earliest version still accepting bugfix PRs; I avoided any changes that were potentially version-specific or referred to anything 3.9 or later.