Cleanup doc testing

[Nerixyz]

What's this all about?

Removes the duplicate doctests. I kept the cargo doc to ensure the documentation always builds.

Fixes: #3204

[kennykerr]

And presumably we can revert the changes to lib.rs for both windows and windows-sys.

[Nerixyz]

And presumably we can revert the changes to lib.rs for both windows and windows-sys.

We could. My thinking behind the change was that the readmes now have links to the samples and the feature search, both of which have a version number in them.