Update manual.md

Author: xushiwei

doc/manual.md

@@ -118,7 +118,7 @@ y.GET("/p/:id", func(ctx *yap.Context) {
 y.Run(":8080")
 ```
 
-demo in Go+ classfile v1 ([main.yap](../demo/classfile_blog/blog_yap.gox)):
+demo in Go+ classfile v1 ([main.yap](../demo/classfile_blog/blog_yap.gox), [article_yap.html](../demo/classfile_blog/yap/article_yap.html)):
 
 ```go
 get "/p/:id", ctx => {