Add Entity.GetTargets which returns IEnumerable

Old GetTarget was removed / made private.

src/gaemstone.ECS/EntityRef.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Linq;
 using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
 using gaemstone.Utility;
@@ -60,7 +61,7 @@ public unsafe class EntityRef
 
 
 	public EntityRef? Parent
-		=> GetTarget(World.ChildOf);
+		=> GetTargets(World.ChildOf).FirstOrDefault();
 
 	public IEnumerable<EntityRef> GetChildren()
 	{
@@ -139,12 +140,14 @@ public unsafe class EntityRef
 		return this;
 	}
 
-	public EntityRef? GetTarget(Entity relation, int index = 0)
+	private EntityRef? GetTarget(Entity relation, int index)
 		=> CreateOrNull(World, new(ecs_get_target(World, this, relation, index)));
-	public EntityRef? GetTarget(string symbol, int index = 0)
-		=> GetTarget(World.LookupBySymbolOrThrow(symbol), index);
-	public EntityRef? GetTarget<T>(int index = 0)
-		=> GetTarget(World.LookupByTypeOrThrow(typeof(T)), index);
+	public IEnumerable<EntityRef> GetTargets(Entity relation)
+		{ var index = 0; while (GetTarget(relation, index++) is EntityRef target) yield return target; }
+	public IEnumerable<EntityRef> GetTargets(string symbol)
+		=> GetTargets(World.LookupBySymbolOrThrow(symbol));
+	public IEnumerable<EntityRef> GetTargets<T>()
+		=> GetTargets(World.LookupByTypeOrThrow(typeof(T)));
 
 	public bool Equals(EntityRef? other) => (other is not null) && (World == other.World) && (Entity == other.Entity);
 	public override bool Equals(object? obj) => Equals(obj as EntityRef);