Fixed XML comment references.

src/Avalonia.Controls/ApplicationLifetimes/ControlledApplicationLifetimeExitEventArgs.cs

@@ -6,7 +6,7 @@ using System;
 namespace Avalonia.Controls.ApplicationLifetimes
 {
     /// <summary>
-    /// Contains the arguments for the <see cref="IClassicDesktopStyleApplicationLifetime.Exit"/> event.
+    /// Contains the arguments for the <see cref="IControlledApplicationLifetime.Exit"/> event.
     /// </summary>
     public class ControlledApplicationLifetimeExitEventArgs : EventArgs
     {

src/Avalonia.Controls/ApplicationLifetimes/StartupEventArgs.cs

@@ -8,7 +8,7 @@ using System.Linq;
 namespace Avalonia.Controls.ApplicationLifetimes
 {
     /// <summary>
-    /// Contains the arguments for the <see cref="IClassicDesktopStyleApplicationLifetime.Startup"/> event.
+    /// Contains the arguments for the <see cref="IControlledApplicationLifetime.Startup"/> event.
     /// </summary>
     public class ControlledApplicationLifetimeStartupEventArgs : EventArgs
     {

src/Avalonia.Controls/ShutdownMode.cs

@@ -1,10 +1,12 @@
 // Copyright (c) The Avalonia Project. All rights reserved.
 // Licensed under the MIT license. See licence.md file in the project root for full license information.
 
+using Avalonia.Controls.ApplicationLifetimes;
+
 namespace Avalonia.Controls
 {
     /// <summary>
-    /// Describes the possible values for <see cref="Application.ShutdownMode"/>.
+    /// Describes the possible values for <see cref="IClassicDesktopStyleApplicationLifetime.ShutdownMode"/>.
     /// </summary>
     public enum ShutdownMode
     {