Instantiate assoc

@[simp] lemma instantiate_assoc [AddCommMonoid ω]    (c : ResourceProfile ω κ)    (impl₁ : κ → ResourceProfile ω κ')    (impl₂ : κ' → ResourceProfile ω κ'') :    (c.instantiate impl₁).instantiate impl₂ =      c.instantiate (fun k ↦ (impl₁ k).instantiate impl₂) := by  have hu : ∀ u : κ →₀ ℕ,      ((ofUsage (ω := ω) u).instantiate impl₁).instantiate impl₂ =        (ofUsage (ω := ω) u).instantiate (fun k ↦ (impl₁ k).instantiate impl₂) := fun u => by    induction u using Finsupp.induction with    | zero => simp [instantiate]    | @single_add a n u ha hn ih =>        have hsplit : ofUsage (ω := ω) (Finsupp.single a n + u) = single a n + ofUsage u := by          ext <;> simp [ofUsage, single]        simp only [hsplit, instantiate_add, instantiate_single, instantiate_nsmul, ih]  have hc : c = ofIntrinsic (κ := κ) c.intrinsic + ofUsage (ω := ω) c.usage := by    ext <;> simp [ofUsage]  rw [hc]  simp only [instantiate_add, instantiate_ofIntrinsic, hu]