feat: setState add a flag to cover state

[day-xue]

[中文版模板 / Chinese template]

useSetState的setMergeState提供一个是否覆盖的标志位

🤔 This is a ...

• New feature
• Bug fix
• Site / documentation update
• Demo update
• TypeScript definition update
• Bundle size optimization
• Performance optimization
• Enhancement feature
• Internationalization
• Refactoring
• Code style optimization
• Test Case
• Branch merge
• Other (about what?)

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💡 Background and solution

📝 Changelog

Language	Changelog
🇺🇸 English
🇨🇳 Chinese

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