Update extensible admission controller links (#9459)

* update extensible-admission-controller links

* correct what-are-initializers link

content/en/docs/reference/access-authn-authz/admission-controllers.md

@@ -26,7 +26,7 @@ is authenticated and authorized.  The controllers consist of the
 administrator. In that list, there are two special controllers:
 MutatingAdmissionWebhook and ValidatingAdmissionWebhook.  These execute the
 mutating and validating (respectively) [admission control
-webhooks](/docs/admin/extensible-admission-controllers.md#external-admission-webhooks)
+webhooks](/docs/reference/access-authn-authz/extensible-admission-controllers/#admission-webhooks)
 which are configured in the API.
 
 Admission controllers may be "validating", "mutating", or both. Mutating
@@ -325,7 +325,7 @@ In any case, the annotations are provided by the user and are not validated by K
 The admission controller determines the initializers of a resource based on the existing
 `InitializerConfiguration`s. It sets the pending initializers by modifying the
 metadata of the resource to be created.
-For more information, please check [Dynamic Admission Control](/docs/admin/extensible-admission-controllers.md).
+For more information, please check [Dynamic Admission Control](/docs/reference/access-authn-authz/extensible-admission-controllers/).
 
 ### LimitPodHardAntiAffinityTopology {#limitpodhardantiaffinitytopology}
 

content/en/docs/reference/command-line-tools-reference/feature-gates.md

@@ -192,7 +192,7 @@ Each feature gate is designed for enabling/disabling a specific feature:
 - `GCERegionalPersistentDisk`: Enable the regional PD feature on GCE.
 - `HugePages`: Enable the allocation and consumption of pre-allocated [huge pages](/docs/tasks/manage-hugepages/scheduling-hugepages/).
 - `HyperVContainer`: Enable [Hyper-V isolation](https://docs.microsoft.com/en-us/virtualization/windowscontainers/manage-containers/hyperv-container) for Windows containers.
-- `Intializers`: Enable the [dynamic admission control](/docs/admin/extensible-admission-controllers/)
+- `Intializers`: Enable the [dynamic admission control](/docs/reference/access-authn-authz/extensible-admission-controllers/)
   as an extension to the built-in [admission controllers](/docs/admin/admission-controllers/).
   When the `Initializers` admission controller is enabled, this feature is automatically enabled.
 - `KubeletConfigFile`: Enable loading kubelet configuration from a file specified using a config file.

content/en/docs/reference/setup-tools/kubeadm/implementation-details.md

@@ -239,7 +239,7 @@ Other API server flags that are set unconditionally are:
  - `--allow-privileged` to `true` (required e.g. by kube proxy)
  - `--requestheader-client-ca-file` to `front-proxy-ca.crt`
  - `--enable-admission-plugins` to:
-    - [`Initializers`](/docs/admin/admission-controllers/#initializers-alpha) to enable [Dynamic Admission Control](/docs/admin/extensible-admission-controllers/).
+    - [`Initializers`](/docs/admin/admission-controllers/#initializers-alpha) to enable [Dynamic Admission Control](/docs/reference/access-authn-authz/extensible-admission-controllers/).
     - [`NamespaceLifecycle`](/docs/admin/admission-controllers/#namespacelifecycle) e.g. to avoid deletion of
       system reserved namespaces
     - [`LimitRanger`](/docs/admin/admission-controllers/#limitranger) and [`ResourceQuota`](/docs/admin/admission-controllers/#resourcequota) to enforce limits on namespaces