Adding a note for default values (Azure#23619)

* Adding a note for default values

Author: jbogard

sdk/identity/Azure.Identity/src/DefaultAzureCredentialOptions.cs

@@ -71,12 +71,14 @@ public class DefaultAzureCredentialOptions : TokenCredentialOptions
         /// <summary>
         /// Specifies whether the <see cref="SharedTokenCacheCredential"/> will be excluded from the <see cref="DefaultAzureCredential"/> authentication flow.
         /// Setting to true disables single sign on authentication with development tools which write to the shared token cache.
+        /// The default is <c>true</c>.
         /// </summary>
         public bool ExcludeSharedTokenCacheCredential { get; set; } = true;
 
         /// <summary>
         /// Specifies whether the <see cref="InteractiveBrowserCredential"/> will be excluded from the <see cref="DefaultAzureCredential"/> authentication flow.
         /// Setting to true disables launching the default system browser to authenticate in development environments.
+        /// The default is <c>true</c>.
         /// </summary>
         public bool ExcludeInteractiveBrowserCredential { get; set; } = true;