message: List existing cluster locator methods in one place
  I found the nested headings difficult to read, so this now lists all
  available methods in one place.
diff: @@ -57,6 +57,10 @@ This is an array used to determine where to retrieve cluster configuration from.
  Valid cluster locator methods are:
  +- [`config`](#config)
  +- [`gke`](#gke)
  +- [custom `KubernetesClustersSupplier`](#custom-kubernetesclusterssupplier)
  +
  #### `config`
  This cluster locator method will read cluster information from your app-config
  