Mentions supports FieldNames, and the tag after @ displays title information

[atom-git]

trafficstars

• [ ] I have searched the issues of this repository and believe that this is not a duplicate.

What problem does this feature solve?

Mentions支持FieldNames与其他选择类组件保持一致，api绑定更简单，@后的tag展示为title信息，更有利于value与呈现分离，与后台接口绑定更顺利

What does the proposed API look like?

fieldNames 自定义节点 label、value、options 的字段 object { label: label, value: value, options: options }