update dumpling code example format

[ran-huang]

What is changed, added or deleted? (Required)

Update dumpling code example format to improve usability.

Which TiDB version(s) do your changes apply to? (Required)

Tips for choosing the affected version(s):

By default, CHOOSE MASTER ONLY so your changes will be applied to the next TiDB major or minor releases. If your PR involves a product feature behavior change or a compatibility change, CHOOSE THE AFFECTED RELEASE BRANCH(ES) AND MASTER.

For details, see tips for choosing the affected versions.

• [x] master (the latest development version)
• [ ] v6.2 (TiDB 6.2 versions)
• [x] v6.1 (TiDB 6.1 versions)
• [x] v5.4 (TiDB 5.4 versions)
• [ ] v5.3 (TiDB 5.3 versions)
• [ ] v5.2 (TiDB 5.2 versions)
• [ ] v5.1 (TiDB 5.1 versions)
• [ ] v5.0 (TiDB 5.0 versions)

What is the related PR or file link(s)?

• This PR is translated from:https://github.com/pingcap/docs-cn/pull/8989
• Other reference link(s):

Do your changes match any of the following descriptions?

• [ ] Delete files
• [ ] Change aliases
• [ ] Need modification after applied to another branch
• [ ] Might cause conflicts after applied to another branch

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has not been approved.

To complete the pull request process, please ask the reviewers in the list to review by filling /cc @reviewer in the comment. After your PR has acquired the required number of LGTMs, you can assign this pull request to the committer in the list by filling /assign @committer in the comment to help you merge this pull request.

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

Reviewer can indicate their review by submitting an approval review. Reviewer can cancel approval by submitting a request changes review.

[ti-chi-bot]

@ran-huang: PR needs rebase.

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.

[qiancai]

Removed the needs-cherry-pick-release-6.3 label because the v6.3 docs have been archived at https://docs-archive.pingcap.com/tidb/v6.3 and will no longer receive new updates.

[qiancai]

Removed the needs-cherry-pick-release-6.4 label because the v6.4 docs have been archived at https://docs-archive.pingcap.com/tidb/v6.4 and will no longer receive new updates.

[ran-huang]

/rebase

[ti-chi-bot[bot]]

[LGTM Timeline notifier]

Timeline:

• 2023-06-13 07:27:44.999334702 +0000 UTC m=+70661.413938781: :ballot_box_with_check: agreed by hfxsd.
• 2023-06-13 07:47:09.509446928 +0000 UTC m=+71825.924051003: :ballot_box_with_check: agreed by Oreoxmt.

[ran-huang]

/approve

[ti-chi-bot[bot]]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: ran-huang

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

The pull request process is described here

Needs approval from an approver in each of these files:

• ~~OWNERS~~ [ran-huang]

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

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-5.4: #13863.

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-6.1: #13864.

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-6.5: #13865.

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-6.6: #13866.

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-7.0: #13867.

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-7.1: #13868.