collections: Tweak docs for push

src/libcollections/lib.rs

@@ -328,10 +328,6 @@ pub trait MutableSet<T>: Set<T> + Mutable {
 pub trait MutableSeq<T>: Mutable {
     /// Append an element to the back of a collection.
     ///
-    /// # Failure
-    ///
-    /// Fails if the number of elements in the vector overflows a `uint`.
-    ///
     /// # Example
     ///
     /// ```rust

src/libcollections/vec.rs

@@ -1557,6 +1557,19 @@ impl<T:fmt::Show> fmt::Show for Vec<T> {
 }
 
 impl<T> MutableSeq<T> for Vec<T> {
+    /// Append an element to the back of a collection.
+    ///
+    /// # Failure
+    ///
+    /// Fails if the number of elements in the vector overflows a `uint`.
+    ///
+    /// # Example
+    ///
+    /// ```rust
+    /// let mut vec = vec!(1i, 2);
+    /// vec.push(3);
+    /// assert_eq!(vec, vec!(1, 2, 3));
+    /// ```
     #[inline]
     fn push(&mut self, value: T) {
         if mem::size_of::<T>() == 0 {