Updated parameter for disabling disk encryption

--volume-type should be -VolumeType in Powershell.

Author: MarileeTurscak-MSFT

articles/security/azure-security-disk-encryption-linux.md

@@ -409,7 +409,7 @@ You can disable encryption using Azure PowerShell, the Azure CLI, or with a Reso
 
 - **Disable disk encryption with Azure PowerShell:** To disable the encryption, use the [Disable-AzVMDisk​Encryption](/powershell/module/az.compute/disable-azvmdiskencryption) cmdlet. 
      ```azurepowershell-interactive
-     Disable-AzVMDiskEncryption -ResourceGroupName 'MyVirtualMachineResourceGroup' -VMName 'MySecureVM' [--volume-type {ALL, DATA, OS}]
+     Disable-AzVMDiskEncryption -ResourceGroupName 'MyVirtualMachineResourceGroup' -VMName 'MySecureVM' [-VolumeType {ALL, DATA, OS}]
      ```
 
 - **Disable encryption with the Azure CLI:** To disable encryption, use the [az vm encryption disable](/cli/azure/vm/encryption#az-vm-encryption-disable) command.