Rollup merge of #126034 - ChrisDenton:winsupport, r=ehuss

Clarify our tier 1 Windows Server support

I've been asked a number of times about our minimum Windows Server support so this PR updates the documentation to be more explicit.

Note that this doesn't change our support at all, it just clarifies it. Windows Server 2016 is the first "Windows 10" server OS (specifically it has the same [build number](https://en.wikipedia.org/wiki/Windows_Server_2016#Release_to_manufacturing) as Windows 10 1607).

Author: workingjubilee