Update vars.md to remove mention of string syntax of node_labels (#7776)
Update vars.md to remove mention of string syntax of node_labels (#7776)

* Update vars.md to remove mention of string syntax of node_labels

Fixes https://github.com/kubernetes-sigs/kubespray/issues/6215

* Try fix makrdown linting

* Update docs/vars.md
Atoms/kubespray,Atoms/kubespray,kubernetes-incubator/kargo,kubernetes-sigs/kubespray,kubernetes-incubator/kargo,kubernetes-incubator/kubespray,kubernetes-incubator/kubespray,kubernetes-sigs/kubespray,kubernetes-sigs/kubespray,Atoms/kubespray,kubernetes-sigs/kubespray,Atoms/kubespray