feat(algebra/big_operators): missing lemmas (#2259)
feat(algebra/big_operators): missing lemmas (#2259)

Co-authored-by: mergify[bot] <b09a6ee808b67e98a221404e7aaa52e0398a4954@users.noreply.github.com>
leanprover-community/mathlib,leanprover-community/mathlib