docs: add LATERAL derived tables documentation

[qiancai]

Document the LATERAL derived table syntax support added in pingcap/tidb#67076. Includes a new page with syntax, examples, and current limitations, plus updates to mysql-compatibility.md and TOC.md.

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• This PR is translated from: docs: add LATERAL derived tables documentation docs#22583
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Auto-sync completed successfully

Source PR: pingcap/docs#22583
Target PR: #21613

Chinese documentation has been updated based on English documentation changes.

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[qiancai]

Suggested change

	* 横向派生表（语法已被识别，但尚不支持执行）[#40328](https://github.com/pingcap/tidb/issues/40328)。有关语法的详细信息，请参阅 [LATERAL Derived Tables](/lateral-derived-tables.md)。
	* 横向派生表（语法可被解析，但尚不支持执行）[#40328](https://github.com/pingcap/tidb/issues/40328)。有关语法的详细信息，请参阅 [LATERAL Derived Tables](/lateral-derived-tables.md)。

[qiancai]

Close this PR because the corresponding doc changes have been merged in #21757.