Windows automatic renewal instructions should use directory hooks for standalone

[alexzorin]

As in #718 for Windows.

Currently the Windows instructions say (emphasis mine):

If you needed to stop your webserver to run Certbot (for example, if you used the standalone authenticator on a machine where port 80 is normally in use), you'll want to edit the built-in command to add the --pre-hook and --post-hook flags to stop and start your webserver automatically

Also, I'm pretty sure Certbot documentation on renewing certificates is meant to be a link - it is in the Linux version. Let's fix that at the same time.