在AspDotNet Core3.1 Swashbuckle中无法获得代码高亮显示

// Startup.cs

using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using Swashbuckle.AspNetCore.Swagger;

public class Startup
{
    public Startup(IConfiguration configuration)
    {
        Configuration = configuration;
    }

    public IConfiguration Configuration { get; }

    public void ConfigureServices(IServiceCollection services)
    {
        services.AddControllers();

        // 添加Swagger生成API文档
        services.AddSwaggerGen(c =>
        {
            c.SwaggerDoc("v1", new Info { Title = "My API", Version = "v1" });
        });
    }

    public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
    {
        if (env.IsDevelopment())
        {
            app.UseDeveloperExceptionPage();
        }

        app.UseRouting();

        app.UseEndpoints(endpoints =>
        {
            endpoints.MapControllers();
        });

        // 启用Swagger中间件
        app.UseSwagger();

        // 配置SwaggerUI，使用自定义的UI模板
        app.UseSwaggerUI(c =>
        {
            c.SwaggerEndpoint("/swagger/v1/swagger.json", "My API V1");
            c.IndexStream = () => GetType().Assembly.GetManifestResourceStream("YourProjectNamespace.Swagger.index.html");
        });
    }
}