Remove SmokeTrailWhenDamaged

One of the most outdated and limited traits remaining,
which can do nothing LeavesTrails doesn't cover by now.

OpenRA.Mods.Common/Traits/SmokeTrailWhenDamaged.cs

@@ -1,68 +0,0 @@
-#region Copyright & License Information
-/*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
- * This file is part of OpenRA, which is free software. It is made
- * available to you under the terms of the GNU General Public License
- * as published by the Free Software Foundation, either version 3 of
- * the License, or (at your option) any later version. For more
- * information, see COPYING.
- */
-#endregion
-
-using System;
-using OpenRA.Mods.Common.Effects;
-using OpenRA.Mods.Common.Traits.Render;
-using OpenRA.Traits;
-
-namespace OpenRA.Mods.Common.Traits
-{
-	class SmokeTrailWhenDamagedInfo : TraitInfo, Requires<BodyOrientationInfo>
-	{
-		[Desc("Position relative to body")]
-		public readonly WVec Offset = WVec.Zero;
-
-		public readonly int Interval = 3;
-
-		public readonly string Sprite = "smokey";
-
-		[SequenceReference(nameof(Sprite))]
-		public readonly string Sequence = "idle";
-
-		public readonly string Palette = "effect";
-
-		public readonly DamageState MinDamage = DamageState.Heavy;
-
-		public override object Create(ActorInitializer init) { return new SmokeTrailWhenDamaged(init.Self, this); }
-	}
-
-	class SmokeTrailWhenDamaged : ITick
-	{
-		readonly SmokeTrailWhenDamagedInfo info;
-		readonly BodyOrientation body;
-		readonly Func<WAngle> getFacing;
-		int ticks;
-
-		public SmokeTrailWhenDamaged(Actor self, SmokeTrailWhenDamagedInfo info)
-		{
-			this.info = info;
-			body = self.Trait<BodyOrientation>();
-			getFacing = RenderSprites.MakeFacingFunc(self);
-		}
-
-		void ITick.Tick(Actor self)
-		{
-			if (--ticks <= 0)
-			{
-				var position = self.CenterPosition;
-				if (position.Z > 0 && self.GetDamageState() >= info.MinDamage && !self.World.FogObscures(self))
-				{
-					var offset = info.Offset.Rotate(body.QuantizeOrientation(self, self.Orientation));
-					var pos = position + body.LocalToWorld(offset);
-					self.World.AddFrameEndTask(w => w.Add(new SpriteEffect(pos, getFacing(), w, info.Sprite, info.Sequence, info.Palette)));
-				}
-
-				ticks = info.Interval;
-			}
-		}
-	}
-}