doc(emacs/README.md): add debian case
doc(emacs/README.md): add debian case

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sp3ctum/lean,soonhokong/lean-windows,leanprover/lean,Kha/lean,rlewis1988/lean,soonhokong/lean-windows,soonhokong/lean-osx,leanprover/lean,leanprover-community/lean,htzh/lean,javra/lean,eigengrau/lean,johoelzl/lean,leanprover-community/lean,htzh/lean,leodemoura/lean,eigengrau/lean,johoelzl/lean,Kha/lean,htzh/lean,dselsam/lean,johoelzl/lean,avigad/lean,fgdorais/lean,levnach/lean,dselsam/lean,fpvandoorn/lean,levnach/lean,digama0/lean,soonhokong/lean-osx,fgdorais/lean,leanprover/lean,fpvandoorn/lean2,leodemoura/lean,sp3ctum/lean,levnach/lean,soonhokong/lean-windows,levnach/lean,javra/lean,fpvandoorn/lean2,soonhokong/lean,johoelzl/lean,c-cube/lean,c-cube/lean,leanprover-community/lean,fpvandoorn/lean,leanprover-community/lean,leodemoura/lean,fpvandoorn/lean,soonhokong/lean,avigad/lean,UlrikBuchholtz/lean,c-cube/lean,soonhokong/lean,fpvandoorn/lean,Kha/lean,johoelzl/lean,soonhokong/lean-osx,c-cube/lean,digama0/lean,fpvandoorn/lean,soonhokong/lean-osx,levnach/lean,javra/lean,javra/lean,Kha/lean,leanprover-community/lean,leodemoura/lean,rlewis1988/lean,fpvandoorn/lean,dselsam/lean,soonhokong/lean,digama0/lean,dselsam/lean,rlewis1988/lean,UlrikBuchholtz/lean,leodemoura/lean,soonhokong/lean-osx,Kha/lean,sp3ctum/lean,rlewis1988/lean,fgdorais/lean,UlrikBuchholtz/lean,leanprover/lean,digama0/lean,digama0/lean,dselsam/lean,avigad/lean,UlrikBuchholtz/lean,leanprover/lean,fgdorais/lean,htzh/lean,johoelzl/lean,Kha/lean,eigengrau/lean,fgdorais/lean,avigad/lean,sp3ctum/lean,javra/lean,soonhokong/lean-windows,sp3ctum/lean,eigengrau/lean,dselsam/lean,avigad/lean,fpvandoorn/lean2,htzh/lean,rlewis1988/lean,rlewis1988/lean,digama0/lean,eigengrau/lean,UlrikBuchholtz/lean,c-cube/lean,soonhokong/lean-windows,fgdorais/lean,leodemoura/lean,leanprover/lean,fpvandoorn/lean2,leanprover-community/lean,soonhokong/lean,fpvandoorn/lean2,avigad/lean