Update the document

Author: wyunchi-ms

src/Aks/Aks/ChangeLog.md

@@ -18,7 +18,7 @@
         - Additional information about change #1
 -->
 ## Upcoming Release
-* Add `Set-AzAksClusterCredential` to reset the ServicePrincipal of a existing aks cluster.
+* Add `Set-AzAksClusterCredential` to reset the ServicePrincipal of an existing AKS cluster.
 
 ## Version 2.0.2
 * Refined error messages of cmdlet failure.

src/Aks/Aks/help/Set-AzAksClusterCredential.md

@@ -8,7 +8,7 @@ schema: 2.0.0
 # Set-AzAksClusterCredential
 
 ## SYNOPSIS
-Reset the ServicePrincipal of a existing aks cluster.
+Reset the ServicePrincipal of an existing AKS cluster.
 
 ## SYNTAX
 
@@ -33,7 +33,7 @@ Set-AzAksClusterCredential [-Id] <String> -ServicePrincipalIdAndSecret <PSCreden
 ```
 
 ## DESCRIPTION
-Reset the ServicePrincipal of a existing aks cluster.
+Reset the ServicePrincipal of an existing AKS cluster.
 
 ## EXAMPLES