Rename remaining first/second to relation/target

src/gaemstone/ECS/Entity.cs

@@ -42,7 +42,7 @@ public readonly struct Entity
 	public static bool operator ==(Entity left, Entity right) =>  left.Equals(right);
 	public static bool operator !=(Entity left, Entity right) => !left.Equals(right);
 
-	public static Identifier operator &(Entity first, Entity second) => Identifier.Pair(first, second);
+	public static Identifier operator &(Entity relation, Entity target) => Identifier.Pair(relation, target);
 
 	public static implicit operator ecs_entity_t(Entity e) => e.Value;
 	public static implicit operator Identifier(Entity e) => new(e.Value.Data);

src/gaemstone/ECS/Term.cs

@@ -8,15 +8,16 @@ public class Term
 {
 	public Identifier ID { get; set; }
 	public TermID? Source { get; set; }
-	public TermID? First { get; set; }
-	public TermID? Second { get; set; }
+	public TermID? Relation { get; set; }
+	public TermID? Target { get; set; }
 	public TermInOutKind InOut { get; set; }
 	public TermOperKind Oper { get; set; }
 	public IdentifierFlags Flags { get; set; }
 
 	public Term() {  }
 	public Term(Identifier id) => ID = id;
-	public Term(TermID first, TermID second) { First = first; Second = second; }
+	public Term(TermID relation, TermID target)
+		{ Relation = relation; Target = target; }
 
 	public static implicit operator Term(EntityRef entity) => new(entity);
 	public static implicit operator Term(Entity    entity) => new(entity);
@@ -34,8 +35,8 @@ public class Term
 	public ecs_term_t ToFlecs(IAllocator allocator) => new() {
 		id       = ID,
 		src      = Source?.ToFlecs(allocator) ?? default,
-		first    = First?.ToFlecs(allocator) ?? default,
-		second   = Second?.ToFlecs(allocator) ?? default,
+		first    = Relation?.ToFlecs(allocator) ?? default,
+		second   = Target?.ToFlecs(allocator) ?? default,
 		inout    = (ecs_inout_kind_t)InOut,
 		oper     = (ecs_oper_kind_t)Oper,
 		id_flags = (ecs_id_t)(ulong)Flags,