fixes example to resemble std more

Author: montekki

src/stream/stream/mod.rs

@@ -149,16 +149,15 @@ pub trait Stream {
  /// # fn main() { async_std::task::block_on(async {
  /// #
  /// use async_std::prelude::*;
- /// use async_std::stream;
+ /// use std::collections::VecDeque;
  ///
- /// let mut s = stream::repeat(9).take(4).enumerate();
- /// let mut c: usize = 0;
+ /// let s: VecDeque<_> = vec!['a', 'b', 'c'].into_iter().collect();
+ /// let mut s = s.enumerate();
+ ///
+ /// assert_eq!(s.next().await, Some((0, 'a')));
+ /// assert_eq!(s.next().await, Some((1, 'b')));
+ /// assert_eq!(s.next().await, Some((2, 'c')));
  ///
- /// while let Some((i, v)) = s.next().await {
- /// assert_eq!(c, i);
- /// assert_eq!(v, 9);
- /// c += 1;
- /// }
  /// #
  /// # }) }
  fn enumerate(self) -> Enumerate<Self>