doc(ITotpService): update inject service document (#5934)

Author: ArgoZhang

src/BootstrapBlazor.Server/Components/Samples/OtpServices.razor

@@ -40,6 +40,8 @@
 
 <p class="code-label mt-3">1. 服务注入</p>
 
+<Pre>services.AddBootstrapBlazorTotpService();</Pre>
+
 <Pre>[Inject]
 [NotNull]
 private ITotpService? TotpService { get; set; }</Pre>