mathlib

af70f8ef - feat(number_theory/bernoulli_polynomials): Added some lemmas (#14282)

feat(number_theory/bernoulli_polynomials): Added some lemmas (#14282) Have added some lemmas regarding rearrangements of sums and evaluations of Bernoulli polynomials. Co-authored-by: Floris van Doorn <fpvdoorn@gmail.com>