Fix Az.NotificationHubs Syntax Errors (Azure#17736)

Author: CaptainFanZzz

src/NotificationHubs/NotificationHubs/help/New-AzNotificationHubsNamespace.md

@@ -41,7 +41,7 @@ The namespace will be located in the West US datacenter and be assigned to the C
 
 ### Example 2: Create a notification hub with tags
 ```powershell
-New-AzNotificationHubsNamespace -ResourceGroup "ContosoNotificationsGroup" -Location "West US" -Namespace "ContosoPartners" -Tags @{Name="Audience";Value="PartnerOrganizations"}
+New-AzNotificationHubsNamespace -ResourceGroup "ContosoNotificationsGroup" -Location "West US" -Namespace "ContosoPartners" -Tag @{Name="Audience";Value="PartnerOrganizations"}
 ```
 
 This command creates a notification hub named ContosoPartners.

src/NotificationHubs/NotificationHubs/help/Remove-AzNotificationHubsNamespaceAuthorizationRule.md

@@ -35,7 +35,7 @@ Removing an authorization rule also removes the corresponding user permission.
 
 ### Example 1: Remove an authorization rule from a namespace
 ```powershell
-Remove-AzNotificationHubNamespaceAuthorizationRule -Namespace "ContosoNamespace" -ResourceGroup "ContosoNotificationsGroup" -AuthorizationRule "ListenRule"
+Remove-AzNotificationHubsNamespaceAuthorizationRule -Namespace "ContosoNamespace" -ResourceGroup "ContosoNotificationsGroup" -AuthorizationRule "ListenRule"
 ```
 
 This command removes the authorization rule named ListenRule from the namespace named ContosoNamespace.