planner: add the doc for the SEMI_JOIN_REWRITE hint (#10607)

[ti-chi-bot]

This is an automated cherry-pick of #10607

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What is changed, added or deleted? (Required)

Add the doc about the new hint.

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• 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)

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• Delete files
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[TomShawn]

/hold
hold until v6.1.1 release

[fixdb]

+1