feat(frontends/lean/decl_attributes): allow user attributes on inductive types
feat(frontends/lean/decl_attributes): allow user attributes on inductive types

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