fix(Analysis/NormedSpace/OperatorNorm): muddled norm and nnnorm (#9473)

This is a lemma about `nnnorm`, but it seems one of the arguments was forgotten.

Mathlib/Analysis/NormedSpace/OperatorNorm.lean

@@ -370,7 +370,7 @@ theorem op_nnnorm_le_of_lipschitz {f : E →SL[σ₁₂] F} {K : ℝ≥0} (hf :
   op_norm_le_of_lipschitz hf
 #align continuous_linear_map.op_nnnorm_le_of_lipschitz ContinuousLinearMap.op_nnnorm_le_of_lipschitz
 
-theorem op_nnnorm_eq_of_bounds {φ : E →SL[σ₁₂] F} (M : ℝ≥0) (h_above : ∀ x, ‖φ x‖ ≤ M * ‖x‖)
+theorem op_nnnorm_eq_of_bounds {φ : E →SL[σ₁₂] F} (M : ℝ≥0) (h_above : ∀ x, ‖φ x‖₊ ≤ M * ‖x‖₊)
     (h_below : ∀ N, (∀ x, ‖φ x‖₊ ≤ N * ‖x‖₊) → M ≤ N) : ‖φ‖₊ = M :=
   Subtype.ext <| op_norm_eq_of_bounds (zero_le M) h_above <| Subtype.forall'.mpr h_below
 #align continuous_linear_map.op_nnnorm_eq_of_bounds ContinuousLinearMap.op_nnnorm_eq_of_bounds