Fix CA2263

OpenRA.Platforms.Default/Sdl2HardwareCursor.cs

@@ -30,7 +30,7 @@ namespace OpenRA.Platforms.Default
 				if (surface == IntPtr.Zero)
 					throw new InvalidDataException($"Failed to create surface: {SDL.SDL_GetError()}");
 
-				var sur = (SDL.SDL_Surface)Marshal.PtrToStructure(surface, typeof(SDL.SDL_Surface));
+				var sur = Marshal.PtrToStructure<SDL.SDL_Surface>(surface);
 				Marshal.Copy(data, 0, sur.pixels, data.Length);
 
 				// This call very occasionally fails on Windows, but often works when retried.

OpenRA.Platforms.Default/VertexBuffer.cs

@@ -17,7 +17,7 @@ namespace OpenRA.Platforms.Default
 	sealed class VertexBuffer<T> : ThreadAffine, IDisposable, IVertexBuffer<T>
 			where T : struct
 	{
-		static readonly int VertexSize = Marshal.SizeOf(typeof(T));
+		static readonly int VertexSize = Marshal.SizeOf<T>();
 		uint buffer;
 		bool disposed;