Added doc for Set and changed single-quotes to double-quotes
Added doc for Set and changed single-quotes to double-quotes

jqs7/gorequest,parnurzeal/gorequest,QuentinPerez/gorequest,kemadz/gorequest,fromkeith/gorequest,csrgxtu/gorequest,going/requests,rockneurotiko/gorequest,julianshen/gorequest,roth1002/gorequest,vicanso/gorequest