modify json utility.
modify json utility.

hellosnow/docfx,sergey-vershinin/docfx,928PJY/docfx,928PJY/docfx,dotnet/docfx,pascalberger/docfx,superyyrrzz/docfx,LordZoltan/docfx,sergey-vershinin/docfx,pascalberger/docfx,hellosnow/docfx,hellosnow/docfx,superyyrrzz/docfx,dotnet/docfx,superyyrrzz/docfx,sergey-vershinin/docfx,dotnet/docfx,pascalberger/docfx,LordZoltan/docfx,LordZoltan/docfx,928PJY/docfx,DuncanmaMSFT/docfx,LordZoltan/docfx,DuncanmaMSFT/docfx