doc: improve some VecDeque examples

Author: tshepang

src/libcollections/vec_deque.rs

@@ -203,7 +203,7 @@ impl<T> VecDeque<T> {
     /// buf.push_back(3);
     /// buf.push_back(4);
     /// buf.push_back(5);
-    /// assert_eq!(buf.get(1).unwrap(), &4);
+    /// assert_eq!(buf.get(1), Some(&4));
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn get(&self, i: usize) -> Option<&T> {
@@ -877,12 +877,14 @@ impl<T> VecDeque<T> {
     ///
     /// let mut buf = VecDeque::new();
     /// assert_eq!(buf.swap_back_remove(0), None);
-    /// buf.push_back(5);
-    /// buf.push_back(99);
-    /// buf.push_back(15);
-    /// buf.push_back(20);
-    /// buf.push_back(10);
-    /// assert_eq!(buf.swap_back_remove(1), Some(99));
+    /// buf.push_back(1);
+    /// buf.push_back(2);
+    /// buf.push_back(3);
+    ///
+    /// assert_eq!(buf.swap_back_remove(0), Some(1));
+    /// assert_eq!(buf.len(), 2);
+    /// assert_eq!(buf[0], 3);
+    /// assert_eq!(buf[1], 2);
     /// ```
     #[unstable(feature = "deque_extras",
                reason = "the naming of this function may be altered")]
@@ -911,12 +913,14 @@ impl<T> VecDeque<T> {
     ///
     /// let mut buf = VecDeque::new();
     /// assert_eq!(buf.swap_front_remove(0), None);
-    /// buf.push_back(15);
-    /// buf.push_back(5);
-    /// buf.push_back(10);
-    /// buf.push_back(99);
-    /// buf.push_back(20);
-    /// assert_eq!(buf.swap_front_remove(3), Some(99));
+    /// buf.push_back(1);
+    /// buf.push_back(2);
+    /// buf.push_back(3);
+    ///
+    /// assert_eq!(buf.swap_front_remove(2), Some(3));
+    /// assert_eq!(buf.len(), 2);
+    /// assert_eq!(buf[0], 2);
+    /// assert_eq!(buf[1], 1);
     /// ```
     #[unstable(feature = "deque_extras",
                reason = "the naming of this function may be altered")]
@@ -1146,12 +1150,12 @@ impl<T> VecDeque<T> {
     /// use std::collections::VecDeque;
     ///
     /// let mut buf = VecDeque::new();
-    /// buf.push_back(5);
-    /// buf.push_back(10);
-    /// buf.push_back(12);
-    /// buf.push_back(15);
-    /// buf.remove(2);
-    /// assert_eq!(Some(&15), buf.get(2));
+    /// buf.push_back(1);
+    /// buf.push_back(2);
+    /// buf.push_back(3);
+    ///
+    /// assert_eq!(buf.remove(1), Some(2));
+    /// assert_eq!(buf.get(1), Some(&3));
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn remove(&mut self, i: usize) -> Option<T> {