优化Comment的位置，用Location代替Position

Runtime/Component/Comment/Comment.cs

@@ -10,7 +10,7 @@ namespace XCharts.Runtime
     /// </summary>
     [Serializable]
     [ComponentHandler(typeof(CommentHander), true)]
-    public class Comment : MainComponent
+    public class Comment : MainComponent, IPropertyChanged
     {
         [SerializeField] private bool m_Show = true;
         [SerializeField] private LabelStyle m_LabelStyle = new LabelStyle();
@@ -65,5 +65,17 @@ namespace XCharts.Runtime
             }
             return m_MarkStyle;
         }
+
+        /// <summary>
+        /// Callback handling when parameters change.
+        /// |参数变更时的回调处理。
+        /// </summary>
+        public void OnChanged()
+        {
+            foreach (var item in items)
+            {
+                item.location.OnChanged();
+            }
+        }
     }
 }