feat(data/mv_polynomial/basic)  induction_on'' (#10621)
feat(data/mv_polynomial/basic)  induction_on'' (#10621)

A new flavor of `induction_on` which is useful when we do not have ` h_add : ∀p q, M p → M q → M (p + q)` but we have
```
h_add_weak : ∀ (a : σ →₀ ℕ) (b : R) (f : (σ →₀ ℕ) →₀ R),  a ∉ f.support → b ≠ 0 → M f → M (monomial a b + f)
```



Co-authored-by: Iván Sadofschi Costa <3cd556df6c016758512187105a01befc6c47b00c@users.noreply.github.com>

leanprover-community/mathlib,leanprover-community/mathlib