Fix cni documentation (#9778)

Signed-off-by: tu1h <lihai.tu@daocloud.io>

docs/cni.md

 CNI
 ==============
 
-This network plugin only unpacks CNI plugins version `cni_version` into `/opt/cni/bin` and instructs kubelet to use cni, that is adds following cli params:
-
-`KUBELET_NETWORK_PLUGIN="--network-plugin=cni --cni-conf-dir=/etc/cni/net.d --cni-bin-dir=/opt/cni/bin"`
+This network plugin only unpacks CNI plugins version `cni_version` into `/opt/cni/bin` and instructs implementation of container runtime cri to use cni.
 
 It's intended usage is for custom CNI configuration, e.g. manual routing tables + bridge + loopback CNI plugin outside kubespray scope. Furthermore, it's used for non-kubespray supported CNI plugins which you can install afterward.