Unify the comment format of C# codes.

codes/csharp/chapter_tree/binary_search_tree.cs

@@ -35,11 +35,7 @@ namespace hello_algo.chapter_tree
             return root;
         }
 
-        /// <summary>
-        /// 查找结点
-        /// </summary>
-        /// <param name="num"></param>
-        /// <returns></returns>
+        /* 查找结点 */
         public TreeNode? search(int num)
         {
             TreeNode? cur = root;

codes/csharp/chapter_tree/binary_tree_bfs.cs

@@ -12,11 +12,7 @@ namespace hello_algo.chapter_tree
     public class binary_tree_bfs
     {
 
-        /// <summary>
-        /// 层序遍历
-        /// </summary>
-        /// <param name="root"></param>
-        /// <returns></returns>
+        /* 层序遍历 */
         public List<int> hierOrder(TreeNode root)
         {
             // 初始化队列，加入根结点

codes/csharp/chapter_tree/binary_tree_dfs.cs

@@ -13,10 +13,7 @@ namespace hello_algo.chapter_tree
     {
         List<int> list = new();
 
-        /// <summary>
-        /// 前序遍历
-        /// </summary>
-        /// <param name="root"></param>
+        /* 前序遍历 */
         void preOrder(TreeNode? root)
         {
             if (root == null) return;
@@ -26,10 +23,7 @@ namespace hello_algo.chapter_tree
             preOrder(root.right);
         }
 
-        /// <summary>
-        /// 中序遍历
-        /// </summary>
-        /// <param name="root"></param>
+        /* 中序遍历 */
         void inOrder(TreeNode? root)
         {
             if (root == null) return;
@@ -39,10 +33,7 @@ namespace hello_algo.chapter_tree
             inOrder(root.right);
         }
 
-        /// <summary>
-        /// 后序遍历
-        /// </summary>
-        /// <param name="root"></param>
+        /* 后序遍历 */
         void postOrder(TreeNode? root)
         {
             if (root == null) return;