Add new instruction to permanently enable completion in the [bash|zsh|fish] shell

[utkarsh-singh1]

What type of PR is this?

/kind bug

What this PR does / why we need it:

kompose completion generate a script that introduces a completion for the shell but this feature does not work for new instance of shell.

Fixes #1966

Special notes for your reviewer:

[utkarsh-singh1]

@cdrage @TessaIO PTAL and can suggest new changes.

[cdrage]

Sorry, but all this PR does is add comments?

[utkarsh-singh1]

/reopen

[k8s-ci-robot]

@utkarsh-singh1: Reopened this PR.

In response to this:

/reopen

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[k8s-ci-robot]

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[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: utkarsh-singh1
Once this PR has been reviewed and has the lgtm label, please assign cdrage for approval. For more information see the Code Review Process.

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

Needs approval from an approver in each of these files:

• OWNERS

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