feat(mention): search event add a prefix param

[chenguzhen87]

Types of changes

• New feature
• Bug fix
• Enhancement
• Component style change
• Typescript definition change
• Documentation change
• Coding style change
• Refactoring
• Test cases
• Continuous integration
• Breaking change
• Others

Background and context

Solution

How is the change tested?

Changelog

Component	Changelog(CN)	Changelog(EN)	Related issues
mention	search 事件增加 prefix 属性	Add prefix attribute to search event	Close #2354

Checklist:

• Test suite passes (npm run test)
• Provide changelog for relevant changes (e.g. bug fixes and new features) if applicable.
• Changes are submitted to the appropriate branch (e.g. features should be submitted to feature branch and others
  should be submitted to main branch)

Other information

[chenguzhen87]

相关issues #2354

[chenguzhen87]

@flsion,有时间帮忙看一下，合一下代码发个版本，项目继续这个功能