修复一些错误并更新README

ExpressionElements/MemberElements/FunctionCall.cs

@@ -10,7 +10,9 @@ using Flee.PublicTypes;
 
 namespace Flee.ExpressionElements.MemberElements
 {
-    [Obsolete("Represents a function call")]
+    /// <summary>
+    /// 表示函数调用的表达式元素
+    /// </summary>
     internal class FunctionCallElement : MemberElement
     {
         private readonly ArgumentList _myArguments;