erl_docgen: Better missing module fault indication
erl_docgen: Better missing module fault indication

If the app or module are incorrect we should return a nice
printout and not just crash when runnig make xmllint

mikpe/otp,emacsmirror/erlang,dumbbell/otp,isvilen/otp,rlipscombe/otp,bjorng/otp,dgud/otp,dumbbell/otp,dumbbell/otp,g-andrade/otp,jj1bdx/otp,bjorng/otp,bjorng/otp,bjorng/otp,dumbbell/otp,emacsmirror/erlang,dgud/otp,erlang/otp,mikpe/otp,isvilen/otp,g-andrade/otp,erlang/otp,isvilen/otp,dgud/otp,rlipscombe/otp,emacsmirror/erlang,potatosalad/otp,isvilen/otp,bjorng/otp,vinoski/otp,dumbbell/otp,rlipscombe/otp,erlang/otp,isvilen/otp,mikpe/otp,vinoski/otp,isvilen/otp,g-andrade/otp,erlang/otp,isvilen/otp,erlang/otp,rlipscombe/otp,dgud/otp,isvilen/otp,emacsmirror/erlang,vinoski/otp,jj1bdx/otp,erlang/otp,dumbbell/otp,dumbbell/otp,mikpe/otp,potatosalad/otp,jj1bdx/otp,mikpe/otp,jj1bdx/otp,rlipscombe/otp,potatosalad/otp,rlipscombe/otp,potatosalad/otp,potatosalad/otp,emacsmirror/erlang,erlang/otp,g-andrade/otp,emacsmirror/erlang,g-andrade/otp,potatosalad/otp,bjorng/otp,dumbbell/otp,bjorng/otp,jj1bdx/otp,dgud/otp,vinoski/otp,potatosalad/otp,potatosalad/otp,dumbbell/otp,emacsmirror/erlang,vinoski/otp,mikpe/otp,bjorng/otp,mikpe/otp,vinoski/otp,vinoski/otp,vinoski/otp,rlipscombe/otp,potatosalad/otp,jj1bdx/otp,jj1bdx/otp,vinoski/otp,erlang/otp,jj1bdx/otp,erlang/otp,jj1bdx/otp,g-andrade/otp,rlipscombe/otp,dgud/otp,g-andrade/otp,mikpe/otp,rlipscombe/otp,dumbbell/otp,emacsmirror/erlang,dgud/otp,dgud/otp,g-andrade/otp,jj1bdx/otp,vinoski/otp,emacsmirror/erlang,potatosalad/otp,bjorng/otp,erlang/otp,isvilen/otp,mikpe/otp,mikpe/otp,dgud/otp,g-andrade/otp,g-andrade/otp,rlipscombe/otp,isvilen/otp,emacsmirror/erlang,bjorng/otp,dgud/otp