Fix brace style

src/Avalonia.Input/AccessKeyHandler.cs

@@ -234,7 +234,8 @@ namespace Avalonia.Input
 
                 case Key.F10:
                     _owner.ShowAccessKeys = _showingAccessKeys = true;
-                    if (MainMenu != null){
+                    if (MainMenu != null)
+                    {
                         MainMenu.Open();
                         e.Handled = true;
                     }