feat(algebra/ordered_group): eq_of_abs_non_pos (#1185)
feat(algebra/ordered_group): eq_of_abs_non_pos (#1185)

* feat(algebra/ordered_group): decidable_linear_ordered_comm_group.eq_of_abs_non_pos

* fix(algebra/ordered_group): new line and name

leanprover-community/mathlib,leanprover-community/mathlib