Make sure to dispose the Discord module and use GTK quit method

Also update Discord Precense when closing a game.

Ryujinx.HLE/FileSystem/Content/ContentManager.cs

@@ -161,7 +161,6 @@ namespace Ryujinx.HLE.FileSystem.Content
                     TimeManager.Instance.InitializeTimeZone(device);
                     device.System.Font.Initialize(this);
                 }
-
             }
         }
 

Ryujinx/Configuration/DiscordIntegrationModule.cs

@@ -88,5 +88,23 @@ namespace Ryujinx.Configuration
 
             DiscordClient?.SetPresence(DiscordPresence);
         }
+
+        public static void SwitchToMainMenu()
+        {
+            DiscordPresence.Details               = "Main Menu";
+            DiscordPresence.State                 = "Idling";
+            DiscordPresence.Assets.LargeImageKey  = "ryujinx";
+            DiscordPresence.Assets.LargeImageText = LargeDescription;
+            DiscordPresence.Assets.SmallImageKey  = null;
+            DiscordPresence.Assets.SmallImageText = null;
+            DiscordPresence.Timestamps            = new Timestamps(DateTime.UtcNow);
+
+            DiscordClient?.SetPresence(DiscordPresence);
+        }
+
+        public static void Exit()
+        {
+            DiscordClient?.Dispose();
+        }
     }
 }

Ryujinx/Ui/MainWindow.cs

@@ -335,6 +335,8 @@ namespace Ryujinx.Ui
             _screen           = null;
             _gameLoaded       = false;
 
+            DiscordIntegrationModule.SwitchToMainMenu();
+
             Application.Invoke(delegate
             {
                 _stopEmulation.Sensitive            = false;
@@ -373,8 +375,9 @@ namespace Ryujinx.Ui
 
             Profile.FinishProfiling();
             device?.Dispose();
+            DiscordIntegrationModule.Exit();
             Logger.Shutdown();
-            Environment.Exit(0);
+            Application.Quit();
         }
 
         private static IRenderer InitializeRenderer()