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.

• master (the latest development version)
• v6.2 (TiDB 6.2 versions)
• v6.1 (TiDB 6.1 versions)
• 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:update dumpling eg format docs-cn#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]

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[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Removed the needs-cherry-pick-release-6.3 label because the v6.3 docs have been archived at https://docs-archive.pingcap.com/tidb/v6.3 and will no longer receive new updates.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Removed the needs-cherry-pick-release-6.4 label because the v6.4 docs have been archived at https://docs-archive.pingcap.com/tidb/v6.4 and will no longer receive new updates.

[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

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

[ran-huang]

/approve

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

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

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• OWNERS [ran-huang]

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[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.