Add doc comments to Host.CreateDefaultBuilder dotnet/extensions#1348 (d…

…otnet/extensions#1409)

Commit migrated from dotnet/extensions@c769e92

src/libraries/Microsoft.Extensions.Hosting/src/Host.cs

@@ -8,11 +8,49 @@
 
 namespace Microsoft.Extensions.Hosting
 {
+    /// <summary>
+    /// Provides convenience methods for creating instances of <see cref="IHostBuilder"/> with pre-configured defaults.
+    /// </summary>
     public static class Host
     {
+        /// <summary>
+        /// Initializes a new instance of the <see cref="HostBuilder"/> class with pre-configured defaults.
+        /// </summary>
+        /// <remarks>
+        ///   The following defaults are applied to the returned <see cref="HostBuilder"/>:
+        ///   <list type="bullet">
+        ///     <item><description>set the <see cref="IHostEnvironment.ContentRootPath"/> to the result of <see cref="Directory.GetCurrentDirectory()"/></description></item>
+        ///     <item><description>load host <see cref="IConfiguration"/> from "DOTNET_" prefixed environment variables</description></item>
+        ///     <item><description>load app <see cref="IConfiguration"/> from 'appsettings.json' and 'appsettings.[<see cref="IHostEnvironment.EnvironmentName"/>].json'</description></item>
+        ///     <item><description>load app <see cref="IConfiguration"/> from User Secrets when <see cref="IHostEnvironment.EnvironmentName"/> is 'Development' using the entry assembly</description></item>
+        ///     <item><description>load app <see cref="IConfiguration"/> from environment variables</description></item>
+        ///     <item><description>configure the <see cref="ILoggerFactory"/> to log to the console, debug, and event source output</description></item>
+        ///     <item><description>enables scope validation on the dependency injecton container when <see cref="IHostEnvironment.EnvironmentName"/> is 'Development'</description></item>
+        ///   </list>
+        /// </remarks>
+        /// <returns>The initialized <see cref="IHostBuilder"/>.</returns>
         public static IHostBuilder CreateDefaultBuilder() =>
             CreateDefaultBuilder(args: null);
 
+        /// <summary>
+        /// Initializes a new instance of the <see cref="HostBuilder"/> class with pre-configured defaults.
+        /// </summary>
+        /// <remarks>
+        ///   The following defaults are applied to the returned <see cref="HostBuilder"/>:
+        ///   <list type="bullet">
+        ///     <item><description>set the <see cref="IHostEnvironment.ContentRootPath"/> to the result of <see cref="Directory.GetCurrentDirectory()"/></description></item>
+        ///     <item><description>load host <see cref="IConfiguration"/> from "DOTNET_" prefixed environment variables</description></item>
+        ///     <item><description>load host <see cref="IConfiguration"/> from supplied command line args</description></item>
+        ///     <item><description>load app <see cref="IConfiguration"/> from 'appsettings.json' and 'appsettings.[<see cref="IHostEnvironment.EnvironmentName"/>].json'</description></item>
+        ///     <item><description>load app <see cref="IConfiguration"/> from User Secrets when <see cref="IHostEnvironment.EnvironmentName"/> is 'Development' using the entry assembly</description></item>
+        ///     <item><description>load app <see cref="IConfiguration"/> from environment variables</description></item>
+        ///     <item><description>load app <see cref="IConfiguration"/> from supplied command line args</description></item>
+        ///     <item><description>configure the <see cref="ILoggerFactory"/> to log to the console, debug, and event source output</description></item>
+        ///     <item><description>enables scope validation on the dependency injecton container when <see cref="IHostEnvironment.EnvironmentName"/> is 'Development'</description></item>
+        ///   </list>
+        /// </remarks>
+        /// <param name="args">The command line args.</param>
+        /// <returns>The initialized <see cref="IHostBuilder"/>.</returns>
         public static IHostBuilder CreateDefaultBuilder(string[] args)
         {
             var builder = new HostBuilder();