collections: Update docs for slice since SliceExt was removed

A lot has changed since this doc text was last touched up, and this is
just a minor edit. I remove the trait section entirely since we don't
use extension traits that much anymore, so there are no significant
trait hilights for this module.

src/libcollections/slice.rs

@@ -13,25 +13,23 @@
 //! The `slice` module contains useful code to help work with slice values.
 //! Slices are a view into a block of memory represented as a pointer and a length.
 //!
-//! ```rust
-//! # #![feature(core)]
+//! ```
 //! // slicing a Vec
-//! let vec = vec!(1, 2, 3);
-//! let int_slice = vec.as_slice();
+//! let vec = vec![1, 2, 3];
+//! let int_slice = &vec[..];
 //! // coercing an array to a slice
 //! let str_slice: &[&str] = &["one", "two", "three"];
 //! ```
 //!
 //! Slices are either mutable or shared. The shared slice type is `&[T]`,
-//! while the mutable slice type is `&mut[T]`. For example, you can mutate the
-//! block of memory that a mutable slice points to:
+//! while the mutable slice type is `&mut [T]`, where `T` represents the element
+//! type. For example, you can mutate the block of memory that a mutable slice
+//! points to:
 //!
-//! ```rust
-//! let x: &mut[i32] = &mut [1, 2, 3];
+//! ```
+//! let x = &mut [1, 2, 3];
 //! x[1] = 7;
-//! assert_eq!(x[0], 1);
-//! assert_eq!(x[1], 7);
-//! assert_eq!(x[2], 3);
+//! assert_eq!(x, &[1, 7, 3]);
 //! ```
 //!
 //! Here are some of the things this module contains:
@@ -41,49 +39,43 @@
 //! There are several structs that are useful for slices, such as `Iter`, which
 //! represents iteration over a slice.
 //!
-//! ## Traits
-//!
-//! A number of traits add methods that allow you to accomplish tasks
-//! with slices, the most important being `SliceExt`. Other traits
-//! apply only to slices of elements satisfying certain bounds (like
-//! `Ord`).
-//!
-//! An example is the `slice` method which enables slicing syntax `[a..b]` that
-//! returns an immutable "view" into a `Vec` or another slice from the index
-//! interval `[a, b)`:
-//!
-//! ```rust
-//! fn main() {
-//!     let numbers = [0, 1, 2];
-//!     let last_numbers = &numbers[1..3];
-//!     // last_numbers is now &[1, 2]
-//! }
-//! ```
-//!
-//! ## Implementations of other traits
+//! ## Trait Implementations
 //!
 //! There are several implementations of common traits for slices. Some examples
 //! include:
 //!
 //! * `Clone`
-//! * `Eq`, `Ord` - for immutable slices whose element type are `Eq` or `Ord`.
+//! * `Eq`, `Ord` - for slices whose element type are `Eq` or `Ord`.
 //! * `Hash` - for slices whose element type is `Hash`
 //!
 //! ## Iteration
 //!
-//! The method `iter()` returns an iteration value for a slice. The iterator
-//! yields references to the slice's elements, so if the element
-//! type of the slice is `isize`, the element type of the iterator is `&isize`.
+//! The slices implement `IntoIterator`. The iterators of yield references
+//! to the slice elements.
 //!
-//! ```rust
-//! let numbers = [0, 1, 2];
-//! for &x in numbers.iter() {
-//!     println!("{} is a number!", x);
+//! ```
+//! let numbers = &[0, 1, 2];
+//! for n in numbers {
+//!     println!("{} is a number!", n);
 //! }
 //! ```
 //!
-//! * `.iter_mut()` returns an iterator that allows modifying each value.
-//! * Further iterators exist that split, chunk or permute the slice.
+//! The mutable slice yields mutable references to the elements:
+//!
+//! ```
+//! let mut scores = [7, 8, 9];
+//! for score in &mut scores[..] {
+//!     *score += 1;
+//! }
+//! ```
+//!
+//! This iterator yields mutable references to the slice's elements, so while the element
+//! type of the slice is `i32`, the element type of the iterator is `&mut i32`.
+//!
+//! * `.iter()` and `.iter_mut()` are the explicit methods to return the default
+//!   iterators.
+//! * Further methods that return iterators are `.split()`, `.splitn()`,
+//!   `.chunks()`, `.windows()` and more.
 
 #![doc(primitive = "slice")]
 #![stable(feature = "rust1", since = "1.0.0")]