Fix IDE0090

OpenRA.Mods.D2k/Traits/Buildings/D2kActorPreviewPlaceBuildingPreview.cs

@@ -25,7 +25,7 @@ namespace OpenRA.Mods.D2k.Traits
 	public class D2kActorPreviewPlaceBuildingPreviewInfo : ActorPreviewPlaceBuildingPreviewInfo
 	{
 		[Desc("Terrain types that should show the 'unsafe' footprint tile.")]
-		public readonly HashSet<string> UnsafeTerrainTypes = new HashSet<string> { "Rock" };
+		public readonly HashSet<string> UnsafeTerrainTypes = new() { "Rock" };
 
 		[Desc("Only check for 'unsafe' footprint tiles when you have these prerequisites.")]
 		public readonly string[] RequiresPrerequisites = Array.Empty<string>();