Make a diagnostic more clear.
Make a diagnostic more clear.

It can be non-obvious why a package is registered more than once.

Peaker/cabal,anton-dessiatov/cabal,corngood/cabal,mmakowski/cabal,seereason/cabal,mydaum/cabal,fugyk/cabal,anton-dessiatov/cabal,fpco/cabal,mydaum/cabal,kolmodin/cabal,fugyk/cabal,eric-stanley/cabal,trskop/cabal,gridaphobe/cabal,mmakowski/cabal,garetxe/cabal,mightybyte/cabal,headprogrammingczar/cabal,kolmodin/cabal,x-y-z/cabal,Peaker/cabal,corngood/cabal,triplepointfive/cabal,gridaphobe/cabal,edsko/cabal,eric-stanley/cabal,bennofs/cabal,randen/cabal,valderman/cabal,beni55/cabal,bennofs/cabal,x-y-z/cabal,plow-technologies/cabal,themoritz/cabal,lukexi/cabal,mightybyte/cabal,thoughtpolice/cabal,randen/cabal,ian-ross/cabal,sopvop/cabal,garetxe/cabal,themoritz/cabal,valderman/cabal,trskop/cabal,thomie/cabal,martinvlk/cabal,plumlife/cabal,sopvop/cabal,seereason/cabal,plumlife/cabal,themoritz/cabal,headprogrammingczar/cabal,ian-ross/cabal,kosmikus/cabal,ghc-android/cabal,rimmington/cabal,gbaz/cabal,Helkafen/cabal,christiaanb/cabal,thoughtpolice/cabal,typelead/epm,enolan/cabal,typelead/epm,edsko/cabal,Heather/cabal,rimmington/cabal,beni55/cabal,gbaz/cabal,lukexi/cabal,Heather/cabal,Helkafen/cabal,christiaanb/cabal,triplepointfive/cabal,fpco/cabal,sopvop/cabal,thomie/cabal,plow-technologies/cabal,kosmikus/cabal,martinvlk/cabal,ghc-android/cabal,enolan/cabal