Update Task.xml (dotnet#8608)

Author: vcrobe

xml/System.Threading.Tasks/Task.xml

@@ -6234,6 +6234,9 @@ The returned task will complete when any of the supplied tasks has completed.  T
 
 The returned task will complete when any of the supplied tasks has completed.  The returned task will always end in the `RanToCompletion` state with its `Result` set to the first task to complete.  The result value is `true` even if the first task to complete ended in the `Canceled` or `Faulted` state.
 
+> [!TIP]
+> In every overloaded version of Task.WhenAny() when this method returns the first completed task, the other tasks will continue running until completion, even any of them completed in the `Canceled` or `Faulted` state. So, if that behavior is not desired you may want to cancel all the remaining tasks once the first task complete.
+
           ]]></format>
         </remarks>
         <exception cref="T:System.ArgumentNullException">