Migrate to .NET 9 (#198)

src/Ryujinx.HLE/HOS/Applets/SoftwareKeyboard/SoftwareKeyboardApplet.cs

@@ -14,6 +14,7 @@ using System.IO;
 using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
 using System.Text;
+using System.Threading;
 
 namespace Ryujinx.HLE.HOS.Applets
 {
@@ -62,7 +63,7 @@ namespace Ryujinx.HLE.HOS.Applets
         private bool _canAcceptController = false;
         private KeyboardInputMode _inputMode = KeyboardInputMode.ControllerAndKeyboard;
 
-        private readonly object _lock = new();
+        private readonly Lock _lock = new();
 
         public event EventHandler AppletStateChanged;
 

src/Ryujinx.HLE/HOS/Applets/SoftwareKeyboard/SoftwareKeyboardRendererBase.cs

@@ -6,6 +6,7 @@ using System.Diagnostics;
 using System.IO;
 using System.Reflection;
 using System.Runtime.InteropServices;
+using System.Threading;
 
 namespace Ryujinx.HLE.HOS.Applets.SoftwareKeyboard
 {
@@ -21,7 +22,7 @@ namespace Ryujinx.HLE.HOS.Applets.SoftwareKeyboard
         const string CancelText = "Cancel";
         const string ControllerToggleText = "Toggle input";
 
-        private readonly object _bufferLock = new();
+        private readonly Lock _bufferLock = new();
 
         private RenderingSurfaceInfo _surfaceInfo = null;
         private SKImageInfo _imageInfo;

src/Ryujinx.HLE/HOS/Applets/SoftwareKeyboard/TimedAction.cs

@@ -27,7 +27,7 @@ namespace Ryujinx.HLE.HOS.Applets.SoftwareKeyboard
 
         private TRef<bool> _cancelled = null;
         private Thread _thread = null;
-        private readonly object _lock = new();
+        private readonly Lock _lock = new();
 
         public bool IsRunning
         {