doc(examples/lean): "dependent" if-then-else example
doc(examples/lean): "dependent" if-then-else example

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

eigengrau/lean,digama0/lean,sp3ctum/lean,avigad/lean,rlewis1988/lean,levnach/lean,javra/lean,fgdorais/lean,leanprover/lean,avigad/lean,johoelzl/lean,sp3ctum/lean,rlewis1988/lean,avigad/lean,dselsam/lean,dselsam/lean,soonhokong/lean-windows,fpvandoorn/lean,leodemoura/lean,leanprover-community/lean,digama0/lean,leanprover-community/lean,soonhokong/lean-windows,soonhokong/lean,eigengrau/lean,dselsam/lean,fpvandoorn/lean2,soonhokong/travis_test,dselsam/lean,Kha/lean,UlrikBuchholtz/lean,leanprover/lean,fpvandoorn/lean,fpvandoorn/lean,javra/lean,johoelzl/lean,fgdorais/lean,levnach/lean,htzh/lean,digama0/lean,soonhokong/lean-osx,rlewis1988/lean,c-cube/lean,soonhokong/lean-osx,johoelzl/lean,soonhokong/lean-osx,digama0/lean,leanprover-community/lean,fgdorais/lean,soonhokong/lean-osx,leodemoura/lean,htzh/lean,rlewis1988/lean,eigengrau/lean,rlewis1988/lean,soonhokong/lean-osx,javra/lean,eigengrau/lean,levnach/lean,dselsam/lean,codyroux/lean0.1,soonhokong/lean-windows,leanprover/lean,soonhokong/travis_test,fpvandoorn/lean2,UlrikBuchholtz/lean,leanprover-community/lean,UlrikBuchholtz/lean,soonhokong/travis_test,soonhokong/lean,c-cube/lean,leanprover-community/lean,johoelzl/lean,UlrikBuchholtz/lean,avigad/lean,digama0/lean,leanprover/lean,soonhokong/lean,leodemoura/lean,c-cube/lean,sp3ctum/lean,UlrikBuchholtz/lean,soonhokong/lean-windows,fpvandoorn/lean,javra/lean,Kha/lean,sp3ctum/lean,codyroux/lean0.1,htzh/lean,leodemoura/lean,soonhokong/lean,sp3ctum/lean,digama0/lean,levnach/lean,c-cube/lean,Kha/lean,htzh/lean,soonhokong/travis_test,javra/lean,johoelzl/lean,leodemoura/lean,fgdorais/lean,fpvandoorn/lean,soonhokong/lean-windows,fpvandoorn/lean,leanprover/lean,levnach/lean,htzh/lean,eigengrau/lean,avigad/lean,dselsam/lean,fgdorais/lean,codyroux/lean0.1,fpvandoorn/lean2,fpvandoorn/lean2,c-cube/lean,leanprover-community/lean,Kha/lean,leodemoura/lean,Kha/lean,leanprover/lean,avigad/lean,fpvandoorn/lean2,codyroux/lean0.1,soonhokong/lean,Kha/lean,fgdorais/lean,johoelzl/lean,rlewis1988/lean