[Doc][Translation] Set local_fallback to en by default
[Doc][Translation] Set local_fallback to en by default

akucherevskiy/developex_test,fhinkel/Silex,Xephi/Silex,CarsonF/Silex,Tobion/Silex,cgsmith/Silex,peterkokot/Silex,naderman/Silex,plotek/Silex,SpacePossum/Silex,mmauri04/Silex,arduanov/Silex,romainneutron/Silex,GromNaN/Silex,Incognito/silex-fork,tcx1000/Silex,fhinkel/Silex,peterkokot/Silex,cesarmarinhorj/Silex,CarsonF/Silex,fabpot/Silex,silexphp/Silex,GromNaN/Silex,CarsonF/Silex,GromNaN/Silex,Tobion/Silex,peterkokot/Silex,naderman/Silex,plotek/Silex,JPry/Silex,akucherevskiy/developex_test,jdreesen/Silex,tcx1000/Silex,lokhman/Silex,mTorres/Silex,romainneutron/Silex,romainneutron/Silex,beealone/Silex,JPry/Silex,cesarmarinhorj/Silex,mathroc/Silex,RayRutjes/Silex,gencer/Silex,mmauri04/Silex,cgsmith/Silex,naderman/Silex,jdreesen/Silex,lokhman/Silex,SanderKnape/Silex,beealone/Silex,Xephi/Silex,arduanov/Silex,akucherevskiy/developex_test,mathroc/Silex,Incognito/silex-fork,mTorres/Silex,Tobion/Silex,fabpot/Silex,SpacePossum/Silex,RayRutjes/Silex,SanderKnape/Silex