Fixed configure-access-multiple-clusters.md

I fixed a Powershell command that you had provided in this document.  Attempting to run the command with the format you supplied resulted in errors due to some conflict between using backwards slash for pathnames inside of parentheses.

Author: afmsavage

content/en/docs/tasks/access-application-cluster/configure-access-multiple-clusters.md

@@ -346,7 +346,7 @@ export KUBECONFIG=$KUBECONFIG:$HOME/.kube/config
 ```
 ### Windows Powershell
 ```shell
-$Env:KUBECONFIG=($Env:KUBECONFIG;$HOME/.kube/config)
+$Env:KUBECONFIG="$Env:KUBECONFIG;$HOME\.kube\config"
 ```
 
 View configuration information merged from all the files that are now listed