see #12: use en-us as default language of readme

DONATE.md

@@ -4,16 +4,17 @@ type: about
 order: 1
 ---
 
+# Donate
+
+I would love if you support me to make the book better:
+
+[![](https://img.shields.io/badge/donate-PayPal-104098.svg?style=popout-square&logo=PayPal)](https://www.paypal.me/ouchangkun/4.99eur)
+
 # 资助
 
 如果你认为本书对你起到了帮助，并希望赞助作者，可以通过下面的二维码给予支持：
 
 |微信|支付宝|
 |:--:|:--:|
-|![](../assets/wechat.jpg) | ![](../assets/alipay.jpg)|
+|![](./assets/wechat.jpg) | ![](./assets/alipay.jpg)|
 
-# Donate
-
-I would love if you support me to make the book better:
-
-[![](https://img.shields.io/badge/donate-PayPal-104098.svg?style=popout-square&logo=PayPal)](https://www.paypal.me/ouchangkun/4.99eur)