Add warnings to features that cannot safely be disabled again.

[markusthoemmes]

Fixes #7241

Proposed Changes

• Adds a warning to the features that cannot safely be disabled after having been enabled once.
• Reorder features a bit to group common features.
• Slightly adjust comments to be consistent.

Release Note

NONE

/assign @mattmoor @dprotaso

[knative-prow-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: markusthoemmes

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Details

Needs approval from an approver in each of these files:

• config/OWNERS [markusthoemmes]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[knative-test-reporter-robot]

The following jobs failed:

Test name	Triggers	Retries
pull-knative-serving-unit-tests		0/3

Failed non-flaky tests preventing automatic retry of pull-knative-serving-unit-tests:

pkg/autoscaler/statforwarder.TestForwarderReconcile

[markusthoemmes]

/retest

[mattmoor]

/lgtm
/hold

This is a great change. @JRBANCEL just added a docs page enumerating these, can we add the same warnings there? Just holding to make sure you see this, feel free to /unhold

[JRBANCEL]

Yes, maybe it should be clarified what cannot b disabled mean in the docs.
It can be disabled but not before every Knative Service using the feature/extension is removed or stops using it.

[markusthoemmes]

@JRBANCEL are you suggesting to add more meat in the CM or just in documentation?

[JRBANCEL]

@JRBANCEL are you suggesting to add more meat in the CM or just in documentation?

In the documentation, it should be enough.

[markusthoemmes]

/unhold

Alrighty then!