Update ReadMe.md

Author: neuecc

ReadMe.md

@@ -942,7 +942,7 @@ If you have other applications such as ASP.NET in the entire project and want to
 // Package Import: Microsoft.Extensions.Hosting
 var builder = Host.CreateApplicationBuilder(); // don't pass args.
 
-using var host = builder.Build(); // using
+using var host = builder.Build(); // use using for host lifetime
 ConsoleApp.ServiceProvider = host.Services; // use host ServiceProvider
 
 ConsoleApp.Run(args, ([FromServices] ILogger<Program> logger) => logger.LogInformation("Hello World!"));
@@ -986,7 +986,7 @@ v4 -> v5 Migration Guide
 v4 was running on top of `Microsoft.Extensions.Hosting`, so build a Host in the same way and set up a ServiceProvider.
 
 ```csharp
-using var host = Host.CreateDefaultBuilder().Build();
+using var host = Host.CreateDefaultBuilder().Build(); // use using for host lifetime
 ConsoleApp.ServiceProvider = host.ServiceProvider;
 ```