* Fix code blocks in set-up-cluster-federation-kubefed
Two of the code blocks don't render correctly in the [docs page](https://kubernetes.io/docs/tasks/federation/set-up-cluster-federation-kubefed/) (see *Adding a cluster to a federation* section) even though they render correctly in the GitHub preview. Hopefully this PR will fix it.
Plus fixed a few instances where the code blocks in set-up-cluster-federation-kubefed.md don't indicate the code block's language.
* Fix spacing