I've run 'make linkcheck' on Doc and it highlighted a number of faulty links in documentation. I've tried fixing some of them and here is the resulting patch. It's a bit too long and touches many files, so to summarise:

* Most changes are http->https redirect (many from wikipedia and microsoft, but some from independent project)
* New domains, sometimes without redirect or any indication of how to find the same information. 
* Completely new locations, only discoverable via search engine.
* Few dead links, that I removed.

I'm going to attach output.txt that is produced after running linkcheck with this patch applied, it is about three time smaller than the original one and has this types of issues:

* Dead links in licenses
* Internal redirects to versioned text
* Many python.org links in whatsnew/ that I don't know what to do about
* Spurious bad links