Fix Az.DesktopVirtualization Syntax Errors (#17572)

Author: v-yuzhichen

src/DesktopVirtualization/help/New-AzWvdHostPool.md

@@ -49,7 +49,7 @@ New-AzWvdHostPool -ResourceGroupName ResourceGroupName `
                             -HostPoolType 'Pooled' `
                             -LoadBalancerType 'DepthFirst' `
                             -RegistrationTokenOperation 'Update' `
-                            -ExpirationTime $((get-date).ToUniversalTime().AddDays(1).ToString('yyyy-MM-ddTHH:mm:ss.fffffffZ')) `
+                            -ExpirationTime $((Get-Date).ToUniversalTime().AddDays(1).ToString('yyyy-MM-ddTHH:mm:ss.fffffffZ')) `
                             -Description 'Description' `
                             -FriendlyName 'Friendly Name' `
                             -MaxSessionLimit 5 `
@@ -79,7 +79,7 @@ New-AzWvdHostPool -ResourceGroupName ResourceGroupName `
                             -HostPoolType 'Personal' `
                             -LoadBalancerType 'Persistent' `
                             -RegistrationTokenOperation 'Update' `
-                            -ExpirationTime $((get-date).ToUniversalTime().AddDays(1).ToString('yyyy-MM-ddTHH:mm:ss.fffffffZ')) `
+                            -ExpirationTime $((Get-Date).ToUniversalTime().AddDays(1).ToString('yyyy-MM-ddTHH:mm:ss.fffffffZ')) `
                             -Description 'Description' `
                             -FriendlyName 'Friendly Name' `
                             -MaxSessionLimit 5 `

src/DesktopVirtualization/help/New-AzWvdRegistrationInfo.md

@@ -24,7 +24,7 @@ Create Windows virtual desktop registration info.
 
 ### Example 1: Create a Windows Virtual Desktop Registration Token
 ```powershell
-New-AzWvdRegistrationInfo -ResourceGroupName ResourceGroupName -HostPoolName HostPoolName -ExpirationTime $((get-date).ToUniversalTime().AddDays(1).ToString('yyyy-MM-ddTHH:mm:ss.fffffffZ'))
+New-AzWvdRegistrationInfo -ResourceGroupName ResourceGroupName -HostPoolName HostPoolName -ExpirationTime $((Get-Date).ToUniversalTime().AddDays(1).ToString('yyyy-MM-ddTHH:mm:ss.fffffffZ'))
 ```
 
 ```output

src/DesktopVirtualization/help/Update-AzWvdDesktop.md

@@ -34,7 +34,7 @@ Update a desktop.
 ### Example 1: Update a Windows Virtual Desktop Desktop
 ```powershell
 Update-AzWvdDesktop -ResourceGroupName ResourceGroupName `
-                             -GroupName ApplicationGroupName `
+                             -ApplicationGroupName ApplicationGroupName `
                              -Name DesktopName `
                              -FriendlyName 'Friendly name' `
                              -Description 'Description' `