modify example of unfold so that it uses the initial_state value
@@ -76,22 +76,21 @@ impl<A, F> Iterator for RepeatCall<F>
///
/// use itertools::unfold;
///
-/// let (mut x1, mut x2) = (1u32, 1u32);
-/// let mut fibonacci = unfold((), move |_| {
+/// let mut fibonacci = unfold((1u32, 1u32), |(x1, x2)| {
/// // Attempt to get the next Fibonacci number
-/// let next = x1.saturating_add(x2);
+/// let next = x1.saturating_add(*x2);
///
/// // Shift left: ret <- x1 <- x2 <- next
-/// let ret = x1;
-/// x1 = x2;
-/// x2 = next;
+/// let ret = *x1;
+/// *x1 = *x2;
+/// *x2 = next;
///
/// // If addition has saturated at the maximum, we are finished
-/// if ret == x1 && ret > 1 {
-/// return None;
-/// }
-///
+/// if ret == *x1 && ret > 1 {
+/// None
+/// } else {
/// Some(ret)
+/// }
/// });
///
/// itertools::assert_equal(fibonacci.by_ref().take(8),
