完善注释和文档

Runtime/Theme/Theme.cs

@@ -277,7 +277,6 @@ namespace XCharts.Runtime
         /// default theme.
         /// ||默认主题。
         /// </summary>
-        /// <value></value>
         public static void ResetToDefaultTheme(Theme theme)
         {
             theme.themeType = ThemeType.Default;
@@ -303,7 +302,6 @@ namespace XCharts.Runtime
         /// dark theme.
         /// ||暗主题。
         /// </summary>
-        /// <value></value>
         public static void ResetToDarkTheme(Theme theme)
         {
             theme.themeType = ThemeType.Dark;

Runtime/Theme/ThemeStyle.cs

@@ -109,7 +109,6 @@ namespace XCharts.Runtime
         /// you can use 'sync color to custom' to synchronize the theme color to the custom color. It can also be set manually.
         /// ||是否自定义主题颜色。当设置为true时，可以用‘sync color to custom’同步主题的颜色到自定义颜色。也可以手动设置。
         /// </summary>
-        /// <value></value>
         public bool enableCustomTheme
         {
             get { return m_EnableCustomTheme; }

Runtime/Theme/VisualMapTheme.cs

@@ -42,7 +42,6 @@ namespace XCharts.Runtime
         /// <summary>
         /// 可视化组件的调节三角形边长。
         /// </summary>
-        /// <value></value>
         public float triangeLen
         {
             get { return m_TriangeLen; }