Use record struct

See
https://www.jetbrains.com/help/rider/UsageOfDefaultStructEquality.html.

osu.Game/Graphics/UserInterface/Hotkey.cs

@@ -11,7 +11,7 @@
 
 namespace osu.Game.Graphics.UserInterface
 {
-    public readonly struct Hotkey
+    public readonly record struct Hotkey
     {
         public KeyCombination[]? KeyCombinations { get; init; }
         public GlobalAction? GlobalAction { get; init; }