docs(plugin-react): add 'preserve' option to JSX runtime

[chenjiahan]

Summary

Updates the documentation for the React plugin, introduce the new preserve option for the runtime setting, along with improved descriptions for all runtime modes and clearer usage guidance for different React versions.

Related Links

• feat(plugin-react): complete preserve React runtime #6240

Checklist

• Tests updated (or not required).
• Documentation updated (or not required).

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[Copilot]

Pull Request Overview

Updates the documentation for the React plugin to introduce the new preserve option for the JSX runtime setting, along with improved organization and descriptions for all runtime modes.

• Added preserve runtime option to type definitions and documentation
• Reorganized runtime documentation with clear subsections for each option
• Enhanced descriptions with usage guidance for different React versions

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
website/docs/zh/plugins/list/plugin-react.mdx	Updated Chinese documentation with new preserve option and restructured runtime sections
website/docs/en/plugins/list/plugin-react.mdx	Updated English documentation with new preserve option and restructured runtime sections

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