refactor(frontends/lean/decl_cmds): cleanup definition_cmd
refactor(frontends/lean/decl_cmds): cleanup definition_cmd

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