doc: update docker.md.

docs/docker.md

@@ -134,6 +134,7 @@ Docker 镜像
 <!--rehype:body-class=cols-2-->
 
 ### 操控
+<!--rehype:wrap-class=row-span-2-->
 
 | `Example` | Description |
 |-----------|-----------|
@@ -159,6 +160,12 @@ $ docker build -f myOtherDockerfile .
 $ curl example.com/remote/Dockerfile | docker build -f - .
 ```
 
+### 删除 \<none> 镜像
+
+```bash
+$ docker rmi -f $(docker images | grep "none" | awk '{print $3}')
+```
+
 Docker 网络
 ----
 <!--rehype:body-class=cols-2-->