docs: Fix broken links

README.md

@@ -115,7 +115,7 @@ $ git pull
 
 ## :handshake: 贡献
 
-在提出 Pull request 之前，请务必先阅读[贡献指南](https://liuyib.github.io/hexo-theme-stun/zh-CN/contribute/)。
+在提出 Pull request 之前，请务必先阅读[贡献指南](https://liuyib.github.io/hexo-theme-stun/zh-CN/contribute/contribute.html)。
 
 感谢所有为 «Stun» 做出贡献的人！
 

README_en-US.md

@@ -115,7 +115,7 @@ If you have problems, please read [documentation](https://liuyib.github.io/hexo-
 
 ## :handshake: Contribution
 
-Please make sure to read the [Contributing Guide](https://liuyib.github.io/hexo-theme-stun/contribute/) before making a pull request.
+Please make sure to read the [Contributing Guide](https://liuyib.github.io/hexo-theme-stun/contribute/contribute.html) before making a pull request.
 
 Thank you to all the people who have already contributed to «Stun»!
 

docs/.vuepress/config.js

@@ -104,7 +104,7 @@ module.exports = {
           },
           {
             text: 'Contribute',
-            link: '/contribute/',
+            link: '/contribute/contribute',
           },
         ],
       },