docs: fix link to Metrics Server user guide
docs: fix link to Metrics Server user guide

kubernetes/kops,aledbf/kops,justinsb/kops,robinpercy/kops,aledbf/kops,robinpercy/kops,kubernetes/kops,robinpercy/kops,kubernetes/kops,aledbf/kops,robinpercy/kops,justinsb/kops,justinsb/kops,aledbf/kops