Add leech to crusher (#17683)

Content.Shared/Weapons/Marker/LeechOnMarkerComponent.cs

@@ -0,0 +1,16 @@
+using Content.Shared.Damage;
+using Robust.Shared.GameStates;
+
+namespace Content.Shared.Weapons.Marker;
+
+/// <summary>
+/// Applies leech upon hitting a damage marker target.
+/// </summary>
+[RegisterComponent, NetworkedComponent]
+public sealed class LeechOnMarkerComponent : Component
+{
+    // TODO: Can't network damagespecifiers yet last I checked.
+    [ViewVariables(VVAccess.ReadWrite)]
+    [DataField("leech", required: true)]
+    public DamageSpecifier Leech = new();
+}