docs(tutorial): update example of multiple writes

[romainwg]

This pull request addresses issue #901 by enhancing the "How to make multiple writes in a transaction" tutorial.

The update includes a new example that demonstrates how to perform multiple write operations within a single transaction.

This addition aims to improve the technical clarity and usefulness of the tutorial by providing a practical demonstration of executing a batch of operations, specifically multiple Put operations, in a single transaction.

This enhancement will help users better understand and implement this functionality in their own projects.

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: romainwg
Once this PR has been reviewed and has the lgtm label, please assign chalin for approval. For more information see the Kubernetes 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

[k8s-ci-robot]

Hi @romainwg. Thanks for your PR.

I'm waiting for a etcd-io 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.

Once the patch is verified, the new status will be reflected by the ok-to-test label.

I understand the commands that are listed here.

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-sigs/prow repository.