mathlib3

68818b3a - feat(field_theory/galois): Is_galois iff is_galois top (#5285)

feat(field_theory/galois): Is_galois iff is_galois top (#5285) Proves that E/F is Galois iff top/F is Galois. Co-authored-by: tb65536 <tb65536@users.noreply.github.com>