Fix the issue that .JSON file is 404 when running docfx serve
Fix the issue that .JSON file is 404 when running docfx serve

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