Complete *-munge-docs.sh deprecation.

[david-mcmahon]

What this PR does / why we need it:
Complete *-munge-docs.sh deprecation.
TOC generation now handled by kubernetes/release#247

Which issue this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close that issue when PR gets merged): fixes #
ref #38309

Special notes for your reviewer:

cc @bgrant0607 @thockin

[k8s-reviewable]

This change is 

[bgrant0607]

Thanks!

/lgtm

[k8s-ci-robot]

@bgrant0607: you can't LGTM a PR unless you are an assignee.

In response to this comment:

Thanks!

/lgtm

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository. I understand the commands that are listed here.

[bgrant0607]

@k8s-bot gci gce e2e test this

[k8s-github-robot]

[APPROVALNOTIFIER] Needs approval from an approver in each of these OWNERS Files:

• hack/OWNERS

We suggest the following people:
cc @jbeda
You can indicate your approval by writing /approve in a comment
You can cancel your approval by writing /approve cancel in a comment

[k8s-github-robot]

@k8s-bot test this [submit-queue is verifying that this PR is safe to merge]

[k8s-ci-robot]

@david-mcmahon: The following test(s) failed:

Test name	Commit	Details	Rerun command
Jenkins kops AWS e2e	902ffd5	link	@k8s-bot kops aws e2e test this

Full PR test history. Your PR dashboard. Please help us cut down on flakes by linking to an open issue when you hit one in your PR.

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository. I understand the commands that are listed here.

[k8s-github-robot]

Automatic merge from submit-queue (batch tested with PRs 39832, 40660)