doc: 更新示例

Author: ArgoZhang

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

@@ -128,7 +128,7 @@
                 <BootstrapInput @bind-Value="@Model.Name" />
             </div>
             <div class="col-12 col-sm-6">
-                <CheckboxList @bind-Value="@SelectedItems" IsButton="true" Items="FooItems" />
+                <CheckboxList @bind-Value="@SelectedItems" IsButton="true" Items="FooItems" ShowLabel="true" DisplayText="Hobby" />
             </div>
         </div>
     </ValidateForm>