chore(doc/lean/lexical): remove obsolete documentation from Lean 0.1
chore(doc/lean/lexical): remove obsolete documentation from Lean 0.1

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