[zh-cn] sync setup-extension-api-server.md

Signed-off-by: SSmallMonster <mingming.zhou@daocloud.io>

content/zh-cn/docs/tasks/extend-kubernetes/setup-extension-api-server.md

@@ -36,7 +36,7 @@ Setting up an extension API server to work the aggregation layer allows the Kube
 <!-- steps -->
 
 <!--
-## Setup an extension api-server to work with the aggregation layer
+## Set up an extension api-server to work with the aggregation layer
 
 The following steps describe how to set up an extension-apiserver *at a high level*. These steps apply regardless if you're using YAML configs or using APIs. An attempt is made to specifically identify any differences between the two. For a concrete example of how they can be implemented using YAML configs, you can look at the [sample-apiserver](https://github.com/kubernetes/sample-apiserver/blob/master/README.md) in the Kubernetes repo.