refactor(library/unifier): cleanup mk_macro_imitation
refactor(library/unifier): cleanup mk_macro_imitation

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

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