This is a Bug Report

Problem:
The Initializer feature gate is removed in 1.14.0 release - kubernetes/kubernetes#72972 .

Proposed Solution:
Update the docs.

Pages to Update:
https://kubernetes.io/docs/reference/command-line-tools-reference/feature-gates/
https://kubernetes.io/docs/reference/access-authn-authz/admission-controllers/#initializers.

/cc @liggitt @spiffxp