✨ docs: fix command-line-tools links in book

[damdo]

What this PR does / why we need it:
Fixes 3 broken link occurrences in the book.
Found them with:

$ grep -r "docs/admin" -l
./docs/book/src/user/concepts.md

After the fix no occurrences are found:

$ grep -r "docs/admin"
$

Which issue(s) this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when PR gets merged):
Fixes #8160

[k8s-ci-robot]

Hi @damdo. Thanks for your PR.

I'm waiting for a kubernetes-sigs 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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[elmiko]

/ok-to-test

cc @oscr

[elmiko]

/lgtm

[k8s-ci-robot]

LGTM label has been added.

Git tree hash: 7a24cdfbe481d1f56fb8317dad8da61b72d11732

[oscr]

Thank you for the quick fix @damdo!

/lgtm
/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: oscr

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[killianmuldoon]

/lgtm

[sbueringer]

/cherry-pick release-1.3

[sbueringer]

/cherry-pick release-1.2

[k8s-infra-cherrypick-robot]

@sbueringer: new pull request created: #8163

In response to this:

/cherry-pick release-1.3

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.

[k8s-infra-cherrypick-robot]

@sbueringer: new pull request created: #8164

In response to this:

/cherry-pick release-1.2

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.