feat(init/setoid): tag equivalence relation
feat(init/setoid): tag equivalence relation

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