fix highlight

Author: alexwolfmsft

docs/azure/sdk/authentication/credential-chains.md

@@ -97,7 +97,7 @@ As more `Exclude`-prefixed properties are set to `true` (credential exclusions a
 
 [ChainedTokenCredential](/dotnet/api/azure.identity.chainedtokencredential?view=azure-dotnet&preserve-view=true) is an empty chain to which you add credentials to suit your app's needs. For example:
 
-:::code language="csharp" source="../snippets/authentication/credential-chains/Program.cs" id="snippet_Ctc" highlight="6-9" :::
+:::code language="csharp" source="../snippets/authentication/credential-chains/Program.cs" id="snippet_Ctc" highlight="6-8" :::
 
 The preceding code sample creates a tailored credential chain comprised of two credentials. The user-assigned managed identity variant of `ManagedIdentityCredential` is attempted first, followed by `VisualStudioCredential`, if necessary. In graphical form, the chain looks like this: