style(lua): use C++-style cast
style(lua): use C++-style cast

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

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