Clarify Iterator::rposition code example

library/core/src/iter/traits/iterator.rs

@@ -2906,14 +2906,14 @@ pub trait Iterator {
     /// Stopping at the first `true`:
     ///
     /// ```
-    /// let a = [1, 2, 3];
+    /// let a = [-1, 2, 3, 4];
     ///
     /// let mut iter = a.iter();
     ///
-    /// assert_eq!(iter.rposition(|&x| x == 2), Some(1));
+    /// assert_eq!(iter.rposition(|&x| x >= 2), Some(3));
     ///
     /// // we can still use `iter`, as there are more elements.
-    /// assert_eq!(iter.next(), Some(&1));
+    /// assert_eq!(iter.next(), Some(&-1));
     /// ```
     #[inline]
     #[stable(feature = "rust1", since = "1.0.0")]