Add Chinese translation of js-spread

This chapter is pretty interesting. ~~'Spread/Rest Attributes' has not got a formal term in Chinese.~~'
~~Personal I translate 'Rest' to '留余', which sounds like literary word.~~'
'Spread' to '展开' which is used by Mozilla's doc. [Spread Operator in Chinese](https://developer.mozilla.org/zh-CN/docs/Web/JavaScript/Reference/Spread_operator) vs [Spread Operator in English](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Spread_operator)
'Rest' to '剩余' which is used by Mozilla's doc. [Rest Parameters in Chinese](https://developer.mozilla.org/zh-CN/docs/Web/JavaScript/Reference/rest_parameters) vs [Rest Parameters in English](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions/rest_parameters)