Adjust docs and tests for new IntoIterator impl for arrays

Author: LukasKalbertodt

std/src/primitive_docs.rs

@@ -498,7 +498,7 @@ mod prim_pointer {}
 /// - [`Copy`]
 /// - [`Clone`]
 /// - [`Debug`]
-/// - [`IntoIterator`] (implemented for `&[T; N]` and `&mut [T; N]`)
+/// - [`IntoIterator`] (implemented for `[T; N]`, `&[T; N]` and `&mut [T; N]`)
 /// - [`PartialEq`], [`PartialOrd`], [`Eq`], [`Ord`]
 /// - [`Hash`]
 /// - [`AsRef`], [`AsMut`]
@@ -526,31 +526,16 @@ mod prim_pointer {}
 /// assert_eq!([1, 2], &array[1..]);
 ///
 /// // This loop prints: 0 1 2
-/// for x in &array {
+/// for x in array {
 ///     print!("{} ", x);
 /// }
 /// ```
 ///
-/// An array itself is not iterable:
-///
-/// ```compile_fail,E0277
-/// let array: [i32; 3] = [0; 3];
-///
-/// for x in array { }
-/// // error: the trait bound `[i32; 3]: std::iter::Iterator` is not satisfied
-/// ```
-///
-/// The solution is to coerce the array to a slice by calling a slice method:
+/// You can also iterate over reference to the array's elements:
 ///
 /// ```
-/// # let array: [i32; 3] = [0; 3];
-/// for x in array.iter() { }
-/// ```
-///
-/// You can also use the array reference's [`IntoIterator`] implementation:
+/// let array: [i32; 3] = [0; 3];
 ///
-/// ```
-/// # let array: [i32; 3] = [0; 3];
 /// for x in &array { }
 /// ```
 ///