add clarification on content-encoding header
add clarification on content-encoding header

vvelikodny/goreq,MeGaPk/goreq,ryansb/goreq,ProjectFrank/goreq,admpub/goreq,sschepens/goreq,appfront/goreq,franela/goreq,dickeyxxx/goreq,gcnonato/goreq,CrowdSurge/goreq,evalphobia/goreq