Change int to i32 in Cow example.

src/libcollections/borrow.rs

@@ -132,7 +132,7 @@ impl<T> ToOwned for T where T: Clone {
 /// ```rust
 /// use std::borrow::Cow;
 ///
-/// fn abs_all(input: &mut Cow<[int]>) {
+/// fn abs_all(input: &mut Cow<[i32]>) {
 ///     for i in 0..input.len() {
 ///         let v = input[i];
 ///         if v < 0 {