Minor documentation fix in NetBuiler
Minor documentation fix in NetBuiler

Summary: Came across this bug in doc when I was figuring out NetBuilder form the code.

Reviewed By: volkhin

Differential Revision: D6341821

fbshipit-source-id: 8818f3d92681366bfe7b90d9d4da9f68ef6e4672

sf-wind/caffe2,davinwang/caffe2,Yangqing/caffe2,pietern/caffe2,xzturn/caffe2,Yangqing/caffe2,sf-wind/caffe2,pietern/caffe2,Yangqing/caffe2,xzturn/caffe2,xzturn/caffe2,davinwang/caffe2,pietern/caffe2,caffe2/caffe2,xzturn/caffe2,pietern/caffe2,xzturn/caffe2,sf-wind/caffe2,Yangqing/caffe2,davinwang/caffe2,pietern/caffe2,davinwang/caffe2,sf-wind/caffe2,Yangqing/caffe2,sf-wind/caffe2,davinwang/caffe2