remove unnecessary es6 template string in fetch schema doc
remove unnecessary es6 template string in fetch schema doc

Summary: Closes https://github.com/facebook/relay/pull/1442

Differential Revision: D4324991

Pulled By: wincent

fbshipit-source-id: d3924227ea72bf38baf57ef889a35ce2d6517669

dbslone/relay,cpojer/relay,benjaminogles/relay,kassens/relay,chentsulin/relay,rosskevin/relay,yungsters/relay,cpojer/relay,wincent/relay,wincent/relay,voideanvalue/relay,xuorig/relay,chirag04/relay,chentsulin/relay,iamchenxin/relay,wincent/relay,voideanvalue/relay,voideanvalue/relay,chirag04/relay,wincent/relay,josephsavona/relay,benjaminogles/relay,josephsavona/relay,iamchenxin/relay,chentsulin/relay,voideanvalue/relay,facebook/relay,facebook/relay,wincent/relay,atxwebs/relay,yungsters/relay,xuorig/relay,kassens/relay,rosskevin/relay,apalm/relay,xuorig/relay,atxwebs/relay,xuorig/relay,wincent/relay,facebook/relay,cpojer/relay,zpao/relay,freiksenet/relay,benjaminogles/relay,apalm/relay,freiksenet/relay,atxwebs/relay,facebook/relay,kassens/relay,facebook/relay,atxwebs/relay,apalm/relay,iamchenxin/relay,iamchenxin/relay,dbslone/relay,kassens/relay,chirag04/relay,voideanvalue/relay,josephsavona/relay,xuorig/relay,kassens/relay,xuorig/relay,zpao/relay,kassens/relay,cpojer/relay,voideanvalue/relay,facebook/relay,yungsters/relay,freiksenet/relay,zpao/relay