Improve in-cluster-client-conf client-go docs

[mattjmcnaughton]

What type of PR is this?
/kind documentation

What this PR does / why we need it:
Make a small formatting change to make it clear that you must take the
RBAC actions regardless of whether you're using Minikube or not.

Which issue(s) this PR fixes:
Fixes #73796

Does this PR introduce a user-facing change?:

NONE

[k8s-ci-robot]

Hi @mattjmcnaughton. Thanks for your PR.

I'm waiting for a kubernetes member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

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[mattjmcnaughton]

/assign @liggitt

thanks!

[liggitt]

/lgtm
/approve
/ok-to-test

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: liggitt, mattjmcnaughton

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• staging/src/k8s.io/client-go/OWNERS [liggitt]

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