mathlib

17412076 - feat(analysis/normed_space/exponential): `Aeᴮ = eᴮA` if `AB = BA` (#13881)

feat(analysis/normed_space/exponential): `Aeᴮ = eᴮA` if `AB = BA` (#13881) This commit shows that the exponenential commutes if the exponent does. This generalizes a previous weaker result.