Update Delete-QuarantineMessage.md

WhatI param Issue #11415

Author: chrisda

exchange/exchange-ps/exchange/Delete-QuarantineMessage.md

@@ -200,9 +200,7 @@ Accept wildcard characters: False
 ```
 
 ### -WhatIf
-The WhatIf switch simulates the actions of the command. You can use this switch to view the changes that would occur without actually applying those changes. You don't need to specify a value with this switch.
-
-The WhatIf switch doesn't work in Security & Compliance PowerShell.
+This parameter is reserved for internal Microsoft use.
 
 ```yaml
 Type: SwitchParameter