Avoid redirection on index page

What does this MR do and why?

I noticed that we have a link to a redirection on the index page, which we should avoid. Let's link directly to target itself.

I noticed this because of this failing job: https://gitlab.com/gitlab-org/gitlab-docs/-/jobs/5649534329.

It looks like we've removed the client-side redirect (nothing in https://gitlab.com/gitlab-org/gitlab/-/tree/master/doc/raketasks?ref_type=heads), and our link checker can't account for a server side redirect (http://docs.gitlab.com/ee/raketasks/backup_restore.html).

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