docs: delete slash (#809)

Author: chaoranz758

content/en/docs/hertz/tutorials/framework-exten/response_writer.md

@@ -77,5 +77,5 @@ Effect display:
 Open the interface in the example at localhost:8888, and then use the following command to observe the effect:
 
 ```bash 
-curl -N --location localhost:8888//flush/chunk
+curl -N --location localhost:8888/flush/chunk
 ```

content/zh/docs/hertz/tutorials/framework-exten/response_writer.md

@@ -68,5 +68,5 @@ Hertz 在 `app.RequestContext` 中提供了 `Response.HijackWriter` 方法让用
 在 localhost:8888 开启示例中的接口，然后使用如下命令观察效果：
 
 ```bash 
-curl -N --location localhost:8888//flush/chunk
+curl -N --location localhost:8888/flush/chunk
 ```