prerequisites doc description make mistake with 'kube-apiserver' and 'kube-controller-manager'

**At this doc :** https://kubesphere.io/docs/installing-on-kubernetes/introduction/prerequisites/
**With the words：**“The CSR signing feature is activated in kube-apiserver when it is started with the --cluster-signing-cert-file and --cluster-signing-key-file parameters. See RKE installation issue.”

**It say:** “in kube-apiserver when it ....”，actually it may be **kube-controller-manager**, not **kube-apiserver**.

Open the prerequisites page linked in the issue and locate the sentence about CSR signing and the --cluster-signing-cert-file and --cluster-signing-key-file parameters. Verify whether kube-controller-manager is the correct component, then update the component name and confirm the rendered documentation no longer identifies kube-apiserver incorrectly.

Written by the indexing model from the issue text.