chore(util/list_fn): fix typo
chore(util/list_fn): fix typo

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

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