Trigger On Hitscan (#40964)

* init

* doc

* merge systems

* review

Content.Shared/Trigger/Components/Triggers/TriggerOnHitscanHitComponent.cs

@@ -0,0 +1,11 @@
+using Robust.Shared.GameStates;
+
+namespace Content.Shared.Trigger.Components.Triggers;
+
+/// <summary>
+/// Component put on the hitscan entity.
+/// Triggers when a hitscan raycast is fired, but only if an entity got hit.
+/// The user is the entity that got hit.
+/// </summary>
+[RegisterComponent, NetworkedComponent, AutoGenerateComponentState]
+public sealed partial class TriggerOnHitscanHitComponent : BaseTriggerOnXComponent;