Clarify TiKV large-row limit in transaction restraints

[doc-claw-bot]

What is changed, added or deleted? (Required)

Clarify in develop/dev-guide-transaction-restraints.md that increasing the TiDB large-row limit alone is not enough. When a single write request exceeds TiKV raftstore.raft-entry-max-size, TiKV rejects the request, so users need to adjust the TiKV limit together with the TiDB row-size limit.

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• v6.5 (TiDB 6.5 versions)
• v6.1 (TiDB 6.1 versions)
• v5.4 (TiDB 5.4 versions)
• v5.3 (TiDB 5.3 versions)

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

• This PR is translated from: Clarify TiKV large-row limit in transaction restraints docs-cn#21830
• Other reference link(s): https://docs.pingcap.com/tidb/dev/dev-guide-transaction-restraints/#large-transaction-restrictions

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

Summary by CodeRabbit

• Documentation
  • Clarified large transaction restrictions by documenting TiKV’s per-request write-size limit.
  • Noted that large-row workloads may require coordinating TiDB and TiKV size settings.

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[coderabbitai]

📝 Walkthrough

Walkthrough

The transaction restrictions guide now notes TiKV’s per-write request limit, its default 8 MiB raftstore.raft-entry-max-size setting, and the need to adjust TiDB and TiKV limits together for large rows.

Changes

Transaction size documentation

Layer / File(s)	Summary
TiKV write request limit develop/dev-guide-transaction-restraints.md	Adds guidance that TiKV rejects single write requests exceeding raftstore.raft-entry-max-size, which defaults to 8 MiB, and that large-row workloads may require changing both TiDB and TiKV limits.

Estimated code review effort: 1 (Trivial) | ~2 minutes

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Title check	✅ Passed	The title clearly and concisely reflects the main documentation change about TiKV's large-row limit.
Description check	✅ Passed	Includes the required change summary, affected versions, references, and branch-modification note; only optional items are omitted.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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