Update the book based on the revised second edition (#1014)

* Revised the book

* Update the book with the second revised edition

* Revise base on the manuscript of the first edition

codes/dart/chapter_hashing/hash_map.dart

@@ -20,7 +20,7 @@ void main() {
   map.forEach((key, value) => print("$key -> $value"));
 
   /* 查询操作 */
-  // 向哈希表输入键 key ，得到值 value
+  // 向哈希表中输入键 key ，得到值 value
   final String? name = map[15937];
   print("\n输入学号 15937 ，查询到姓名 $name");