Add lightning log message explanation doc

[db-will]

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Added doc to explain lightning log message, since it binds with specific tidb version. so we add it as part of 5.4 release currently

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This pull request has been approved by:

• lance6716

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[lance6716]

And for other versions, we still can add a link to this v5.4-specific page?

[db-will]

@lance6716 thanks for reviewing. just updated

[db-will]

@ran-huang could please you review the pr again?

[ran-huang]

@ran-huang could please you review the pr again?

Sure. Thanks for the reminder!

[ran-huang]

/merge

[ti-chi-bot]

This pull request has been accepted and is ready to merge.

Commit hash: e9aae43