fix(docs): Minor typographical fix (#2992)
fix(docs): Minor typographical fix (#2992)

Summary:
Minor grammatical tweak.
Pull Request resolved: https://github.com/facebook/relay/pull/2992

Differential Revision: D19373923

Pulled By: jstejada

fbshipit-source-id: c4bc29dec74788ebbbaa67f9023bded60f25a603

josephsavona/relay,xuorig/relay,yungsters/relay,wincent/relay,facebook/relay,iamchenxin/relay,yungsters/relay,iamchenxin/relay,facebook/relay,facebook/relay,voideanvalue/relay,facebook/relay,voideanvalue/relay,xuorig/relay,atxwebs/relay,cpojer/relay,xuorig/relay,cpojer/relay,voideanvalue/relay,josephsavona/relay,wincent/relay,facebook/relay,voideanvalue/relay,kassens/relay,atxwebs/relay,kassens/relay,atxwebs/relay,voideanvalue/relay,kassens/relay,xuorig/relay,iamchenxin/relay,voideanvalue/relay,wincent/relay,kassens/relay,cpojer/relay,iamchenxin/relay,xuorig/relay,facebook/relay,kassens/relay,wincent/relay,josephsavona/relay,cpojer/relay,yungsters/relay,wincent/relay,atxwebs/relay,xuorig/relay,kassens/relay,wincent/relay