Update the code snippet of 'Use HTTP error handling' in httpclient.md / No.1 (#48218)

Author: fcdeveloper00

docs/fundamentals/networking/snippets/httpclient/Program.CancellationInnerTimeout.cs

@@ -3,16 +3,18 @@
     static async Task WithCancellationAndInnerTimeoutAsync(HttpClient httpClient)
     {
         // <innertimeout>
+        using var cts = new CancellationTokenSource();
         try
         {
             // Assuming:
             //   httpClient.Timeout = TimeSpan.FromSeconds(10)
 
             using var response = await httpClient.GetAsync(
-                "http://localhost:5001/sleepFor?seconds=100");
+                "http://localhost:5001/sleepFor?seconds=100", cts.Token);
         }
         catch (OperationCanceledException ex) when (ex.InnerException is TimeoutException tex)
         {
+            // when the time-out occurred. Here the cancellation token has not been canceled.
             Console.WriteLine($"Timed out: {ex.Message}, {tex.Message}");
         }
         // </innertimeout>