[Static web assets] Add comment about static web assets in CreateDefaultBuilder (#20653)

Updates the existing comment to indicate that we plug-in static web assets in development

Author: javiercn

src/DefaultBuilder/src/GenericHostBuilderExtensions.cs

@@ -15,6 +15,7 @@ public static class GenericHostBuilderExtensions
         /// <remarks>
         ///   The following defaults are applied to the <see cref="IWebHostBuilder"/>:
         ///     use Kestrel as the web server and configure it using the application's configuration providers,
+        ///     configure the <see cref="IWebHostEnvironment.WebRootFileProvider"/> to map static web assets when <see cref="IHostEnvironment.EnvironmentName"/> is 'Development' using the entry assembly,
         ///     adds the HostFiltering middleware,
         ///     adds the ForwardedHeaders middleware if ASPNETCORE_FORWARDEDHEADERS_ENABLED=true,
         ///     and enable IIS integration.

src/DefaultBuilder/src/WebHost.cs

@@ -146,6 +146,7 @@ public static IWebHostBuilder CreateDefaultBuilder() =>
         ///     load <see cref="IConfiguration"/> from environment variables,
         ///     load <see cref="IConfiguration"/> from supplied command line args,
         ///     configure the <see cref="ILoggerFactory"/> to log to the console and debug output,
+        ///     configure the <see cref="IWebHostEnvironment.WebRootFileProvider"/> to map static web assets when <see cref="IHostEnvironment.EnvironmentName"/> is 'Development' using the entry assembly,
         ///     adds the HostFiltering middleware,
         ///     adds the ForwardedHeaders middleware if ASPNETCORE_FORWARDEDHEADERS_ENABLED=true,
         ///     and enable IIS integration.