fix: Make the first exercise editable in 10.3

src/collections/hashmap.md

@@ -10,6 +10,7 @@ The hash table implementation is a Rust port of Google’s [SwissTable](https://
 1. 🌟🌟
 
 ```rust,editbale
+
 // FILL in the blanks and FIX the erros
 use std::collections::HashMap;
 fn main() {

zh-CN/src/collections/hashmap.md

@@ -7,6 +7,7 @@
 1. 🌟🌟
 
 ```rust,editbale
+
 // 填空并修复错误
 use std::collections::HashMap;
 fn main() {