mathlib3

b1f44ba1 - chore(group_theory/free_group,order/zorn): rename zorn.zorn and sum.sum (#1604)

chore(group_theory/free_group,order/zorn): rename zorn.zorn and sum.sum (#1604) * chore(order/zorn): rename zorn.zorn * chore(group_theory/free_group): rename sum.sum * chore(group_theory/free_group,order/zorn): remove nolint