mathlib3

b7cba576 - chore(set_theory/game/*): Protect ambiguous lemmas (#13557)

chore(set_theory/game/*): Protect ambiguous lemmas (#13557) Protect `pgame.neg_zero` and inline `pgame.add_le_add_left` and friends into `covariant_class` instances. Co-authored-by: Violeta Hernández <vi.hdz.p@gmail.com>