Convert no longer necessary lambda expressions to method groups

Author: Joehuu

osu.Framework/Extensions/TypeExtensions/TypeExtensions.cs

@@ -116,8 +116,7 @@ public static Type GetUnderlyingNullableType(this Type type)
             if (!type.IsGenericType)
                 return null;
 
-            // ReSharper disable once ConvertClosureToMethodGroup (see: https://github.com/dotnet/runtime/issues/33747)
-            return underlying_type_cache.GetOrAdd(type, t => Nullable.GetUnderlyingType(t));
+            return underlying_type_cache.GetOrAdd(type, Nullable.GetUnderlyingType);
         }
 
         /// <summary>

osu.Framework/Input/Bindings/KeyBindingContainer.cs

@@ -232,12 +232,9 @@ private bool handleNewPressed(InputState state, InputKey newKey, Vector2? scroll
             if (KeyCombination.IsModifierKey(newKey))
             {
                 // if the current key pressed was a modifier, only handle modifier-only bindings.
-                // lambda expression is used so that the delegate is cached (see: https://github.com/dotnet/roslyn/issues/5835)
-                // TODO: remove when we switch to .NET 7.
-                // ReSharper disable once ConvertClosureToMethodGroup
                 for (int i = 0; i < newlyPressed.Count; i++)
                 {
-                    if (!newlyPressed[i].KeyCombination.Keys.All(key => KeyCombination.IsModifierKey(key)))
+                    if (!newlyPressed[i].KeyCombination.Keys.All(KeyCombination.IsModifierKey))
                         newlyPressed.RemoveAt(i--);
                 }
             }

osu.Framework/Platform/Windows/WindowsMouseHandler_SDL2.cs

@@ -27,8 +27,7 @@ internal partial class WindowsMouseHandler
 
         private void initialiseSDL2(GameHost host)
         {
-            // ReSharper disable once ConvertClosureToMethodGroup
-            sdl2Callback = (ptr, wnd, u, param, l) => onWndProcSDL2(ptr, wnd, u, param, l);
+            sdl2Callback = onWndProcSDL2;
 
             Enabled.BindValueChanged(enabled =>
             {