增加代码API注释文档，整理代码

Scripts/UI/Internal/AxisLine.cs

@@ -2,23 +2,61 @@ using UnityEngine;
 
 namespace XCharts
 {
-    [System.Serializable]
+    /// <summary>
+    /// Settings related to axis line.
+    /// 坐标轴的分隔线。
+    /// </summary>
+    [System.Serializable]    
     public class AxisLine
     {
         [SerializeField] private bool m_Show;
         [SerializeField] private bool m_OnZero;
+        [SerializeField] private float m_Width = 0.6f;
         [SerializeField] private bool m_Symbol;
         [SerializeField] private float m_SymbolWidth;
         [SerializeField] private float m_SymbolHeight;
         [SerializeField] private float m_SymbolOffset;
         [SerializeField] private float m_SymbolDent;
 
+        /// <summary>
+        /// Set this to false to prevent the axis line from showing.
+        /// 是否显示坐标轴轴线。
+        /// </summary>
         public bool show { get { return m_Show; } set { m_Show = value; } }
+        /// <summary>
+        /// When mutiple axes exists, this option can be used to specify which axis can be "onZero" to.
+        /// X 轴或者 Y 轴的轴线是否在另一个轴的 0 刻度上，只有在另一个轴为数值轴且包含 0 刻度时有效。
+        /// </summary>
         public bool onZero { get { return m_OnZero; } set { m_OnZero = value; } }
+        /// <summary>
+        /// line style line width.
+        /// 坐标轴线线宽。
+        /// </summary>
+        public float width { get { return m_Width; } set { m_Width = value; } }
+        /// <summary>
+        /// Whether to show the arrow symbol of axis. 
+        /// 是否显示箭头。
+        /// </summary>
         public bool symbol { get { return m_Symbol; } set { m_Symbol = value; } }
+        /// <summary>
+        /// the width of arrow symbol. 
+        /// 箭头宽。
+        /// </summary>
         public float symbolWidth { get { return m_SymbolWidth; } set { m_SymbolWidth = value; } }
+        /// <summary>
+        /// the height of arrow symbol. 
+        /// 箭头高。
+        /// </summary>
         public float symbolHeight { get { return m_SymbolHeight; } set { m_SymbolHeight = value; } }
+        /// <summary>
+        /// the offset of arrow symbol. 
+        /// 箭头偏移。
+        /// </summary>
         public float symbolOffset { get { return m_SymbolOffset; } set { m_SymbolOffset = value; } }
+        /// <summary>
+        /// the dent of arrow symbol. 
+        /// 箭头的凹陷程度。
+        /// </summary>
         public float symbolDent { get { return m_SymbolDent; } set { m_SymbolDent = value; } }
 
         public static AxisLine defaultAxisLine
@@ -29,6 +67,7 @@ namespace XCharts
                 {
                     m_Show = true,
                     m_OnZero = true,
+                    m_Width = 0.7f,
                     m_Symbol = false,
                     m_SymbolWidth = 10,
                     m_SymbolHeight = 15,