CPUCFSQuotaPeriod - CLI Reference mismatch (#14090)

`CPUCFSQuotaPeriod` Feature Gate is set from the flag name `CustomCPUCFSQuotaPeriod` per [`kube_features.go#163`](https://github.com/kubernetes/kubernetes/blob/master/pkg/features/kube_features.go#L163)
This PR updates the docs to suit.

In some respects it would be tidier to remove `Custom` prefix from `kube_features.go` so that the Feature Gate naming maps 1:1.
Happy to close this PR and do PR to remove 'Custom' prefix instead.

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

@@ -50,7 +50,6 @@ different Kubernetes components.
 | `BlockVolume` | `false` | Alpha | 1.9 | |
 | `BlockVolume` | `true` | Beta | 1.13 | - |
 | `BoundServiceAccountTokenVolume` | `false` | Alpha | 1.13 | |
-| `CPUCFSQuotaPeriod` | `false` | Alpha | 1.12 | |
 | `CPUManager` | `false` | Alpha | 1.8 | 1.9 |
 | `CPUManager` | `true` | Beta | 1.10 | |
 | `CRIContainerLogRotation` | `false` | Alpha | 1.10 | 1.10 |
@@ -68,6 +67,7 @@ different Kubernetes components.
 | `CSIPersistentVolume` | `false` | Alpha | 1.9 | 1.9 |
 | `CSIPersistentVolume` | `true` | Beta | 1.10 | 1.12 |
 | `CSIPersistentVolume` | `true` | GA | 1.13 | - |
+| `CustomCPUCFSQuotaPeriod` | `false` | Alpha | 1.12 | |
 | `CustomPodDNS` | `false` | Alpha | 1.9 | 1.9 |
 | `CustomPodDNS` | `true` | Beta| 1.10 | |
 | `CustomResourceSubresources` | `false` | Alpha | 1.10 | 1.11 |
@@ -219,7 +219,6 @@ Each feature gate is designed for enabling/disabling a specific feature:
    ServiceAccountTokenVolumeProjection.
    Check [Service Account Token Volumes](https://git.k8s.io/community/contributors/design-proposals/storage/svcacct-token-volume-source.md)
    for more details.
-- `CPUCFSQuotaPeriod`: Enable nodes to change CPUCFSQuotaPeriod.
 - `CPUManager`: Enable container level CPU affinity support, see [CPU Management Policies](/docs/tasks/administer-cluster/cpu-management-policies/).
 - `CRIContainerLogRotation`: Enable container log rotation for cri container runtime.
 - `CSIBlockVolume`: Enable external CSI volume drivers to support block storage. See the [`csi` raw block volume support](/docs/concepts/storage/volumes/#csi-raw-block-volume-support) documentation for more details.
@@ -233,6 +232,7 @@ Each feature gate is designed for enabling/disabling a specific feature:
   [CSI (Container Storage Interface)](https://github.com/kubernetes/community/blob/master/contributors/design-proposals/storage/container-storage-interface.md)
   compatible volume plugin.
   Check the [`csi` volume type](/docs/concepts/storage/volumes/#csi) documentation for more details.
+- `CustomCPUCFSQuotaPeriod`: Enable nodes to change CPUCFSQuotaPeriod.
 - `CustomPodDNS`: Enable customizing the DNS settings for a Pod using its `dnsConfig` property.
    Check [Pod's DNS Config](/docs/concepts/services-networking/dns-pod-service/#pods-dns-config)
    for more details.