chore(library/standard/data/nat/div): remove TODO
chore(library/standard/data/nat/div): remove TODO

Signed-off-by: Leonardo de Moura <7610bae85f2b530654cc716772f1fe653373e892@microsoft.com>

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