Merge branch 'master' of https://github.com/sunface/rust-by-practice into edit

en/src/collections/intro.md

@@ -3,4 +3,3 @@ Learning resources:
 - English: [Rust Book Chapter 8](https://doc.rust-lang.org/book/ch08-00-common-collections.html)
 - 简体中文: [Rust语言圣经 - 集合类型](https://course.rs/basic/collections/intro.html)
 
-

en/src/smart-pointers/intro.md

@@ -1 +1,3 @@
 # Smart pointers
+
+<!-- https://github.com/marvinguo/rust-best-practices/tree/main/examples -->

en/src/why-exercise.md

@@ -1,5 +1,5 @@
 <div align="center">
-    <img  src="https://github.com/sunface/rust-by-practice/blob/master/en/assets/header.png?raw=true">
+    <img  src="https://github.com/sunface/rust-by-practice/blob/master/en/assets/header.jpg?raw=true">
 </div>
     
 <p align="center">Practice Rust with challenging examples, exercises and projects</p>