feat(kernel/type_checker): make sure anonymous binder names are rejected by the kernel
feat(kernel/type_checker): make sure anonymous binder names are rejected by the kernel

digama0/lean,dselsam/lean,johoelzl/lean,leanprover-community/lean,leodemoura/lean,avigad/lean,avigad/lean,leanprover/lean,dselsam/lean,johoelzl/lean,fgdorais/lean,avigad/lean,dselsam/lean,rlewis1988/lean,leanprover/lean,Kha/lean,rlewis1988/lean,johoelzl/lean,leanprover-community/lean,fpvandoorn/lean,digama0/lean,rlewis1988/lean,leodemoura/lean,fgdorais/lean,rlewis1988/lean,avigad/lean,leodemoura/lean,digama0/lean,fpvandoorn/lean,dselsam/lean,fgdorais/lean,johoelzl/lean,fpvandoorn/lean,avigad/lean,fpvandoorn/lean,leanprover-community/lean,leanprover/lean,Kha/lean,Kha/lean,Kha/lean,johoelzl/lean,fgdorais/lean,leodemoura/lean,leanprover/lean,leanprover-community/lean,leodemoura/lean,digama0/lean,fpvandoorn/lean,rlewis1988/lean,leanprover-community/lean,digama0/lean,leanprover/lean,Kha/lean,fgdorais/lean,rlewis1988/lean,fgdorais/lean,dselsam/lean,leanprover/lean,leanprover-community/lean,digama0/lean,leodemoura/lean,avigad/lean,johoelzl/lean,dselsam/lean,Kha/lean,fpvandoorn/lean