ddressed review comments

Author: liyinan926

docs/running-on-kubernetes.md

@@ -186,7 +186,8 @@ To use a secret through an environment variable use the following options to the
 ```
 
 ## Using Kubernetes Volumes
-Starting Spark 2.4.0, users can mount the following types of Kubernetes [volumes](https://kubernetes.io/docs/concepts/storage/volumes/) into the driver and executor pods:
+
+Starting with Spark 2.4.0, users can mount the following types of Kubernetes [volumes](https://kubernetes.io/docs/concepts/storage/volumes/) into the driver and executor pods:
 * [hostPath](https://kubernetes.io/docs/concepts/storage/volumes/#hostpath): mounts a file or directory from the host node’s filesystem into a pod.
 * [emptyDir](https://kubernetes.io/docs/concepts/storage/volumes/#emptydir): an initially empty volume created when a pod is assigned to a node.
 * [persistentVolumeClaim](https://kubernetes.io/docs/concepts/storage/volumes/#persistentvolumeclaim): used to mount a `PersistentVolume` into a pod.