docs(probability/martingale): missing word (#13113)

src/probability/martingale.lean

@@ -323,7 +323,7 @@ integrable_stopped_value hτ hf.integrable hbdd
 -- Similarly, generalize `(super/)submartingale.set_integral_le`.
 
 /-- Given a submartingale `f` and bounded stopping times `τ` and `π` such that `τ ≤ π`, the
-expectation of `stopped_value f τ` is less or equal to the expectation of `stopped_value f π`.
+expectation of `stopped_value f τ` is less than or equal to the expectation of `stopped_value f π`.
 This is the forward direction of the optional stopping theorem. -/
 lemma expected_stopped_value_mono {f : ℕ → α → ℝ} (hf : submartingale f 𝒢 μ) {τ π : α → ℕ}
   (hτ : is_stopping_time 𝒢 τ) (hπ : is_stopping_time 𝒢 π) (hle : τ ≤ π)