feat(circle): prove the path computation rule for the circle
feat(circle): prove the path computation rule for the circle

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