feat(frontends/lean/elaborator): structure notation: synthesize instance-implicit fields
feat(frontends/lean/elaborator): structure notation: synthesize instance-implicit fields

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