refactot(script) : 调整了脚本执行相关代码（但后续这个脚本会新的DSL被代替），故不再进行调整

Serein.Script/Node/TypeNode.cs

@@ -11,6 +11,9 @@ namespace Serein.Script.Node
     /// </summary>
     public class TypeNode : ASTNode
     {
+        /// <summary>
+        /// 类型名称
+        /// </summary>
         public string TypeName { get;  }
 
         public TypeNode(string typeName)

Serein.Script/Node/UsingNode.cs

@@ -0,0 +1,23 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Serein.Script.Node
+{
+    internal class UsingNode : ASTNode
+    {
+        public string Namespace { get; }
+
+        public UsingNode(string @namespace)
+        {
+            Namespace = @namespace;
+        }
+
+        public override string ToString()
+        {
+            return $"using Namespace";
+        }
+    }
+}