DOC: In From impls, move the documentation down to the method

Once upon a time, rustdoc only supported the doc on top of the impl. Now
it can be on the method.

And it looks like if we have doc for `from`, then the link from the
conversions table works (because the from method is now expanded by
default).

Author: bluss

src/arraytraits.rs

@@ -215,13 +215,12 @@ pub const ARRAY_FORMAT_VERSION: u8 = 1u8;
 
 // use "raw" form instead of type aliases here so that they show up in docs
 /// Implementation of `ArrayView::from(&S)` where `S` is a slice or slicable.
-///
-/// Create a one-dimensional read-only array view of the data in `slice`.
-///
-/// **Panics** if the slice length is greater than `isize::MAX`.
 impl<'a, A, Slice: ?Sized> From<&'a Slice> for ArrayView<'a, A, Ix1>
     where Slice: AsRef<[A]>
 {
+    /// Create a one-dimensional read-only array view of the data in `slice`.
+    ///
+    /// **Panics** if the slice length is greater than `isize::MAX`.
     fn from(slice: &'a Slice) -> Self {
         let xs = slice.as_ref();
         if mem::size_of::<A>() == 0 {
@@ -237,25 +236,23 @@ impl<'a, A, Slice: ?Sized> From<&'a Slice> for ArrayView<'a, A, Ix1>
 }
 
 /// Implementation of `ArrayView::from(&A)` where `A` is an array.
-///
-/// Create a read-only array view of the array.
 impl<'a, A, S, D> From<&'a ArrayBase<S, D>> for ArrayView<'a, A, D>
     where S: Data<Elem=A>,
           D: Dimension,
 {
+    /// Create a read-only array view of the array.
     fn from(array: &'a ArrayBase<S, D>) -> Self {
         array.view()
     }
 }
 
 /// Implementation of `ArrayViewMut::from(&mut S)` where `S` is a slice or slicable.
-///
-/// Create a one-dimensional read-write array view of the data in `slice`.
-///
-/// **Panics** if the slice length is greater than `isize::MAX`.
 impl<'a, A, Slice: ?Sized> From<&'a mut Slice> for ArrayViewMut<'a, A, Ix1>
     where Slice: AsMut<[A]>
 {
+    /// Create a one-dimensional read-write array view of the data in `slice`.
+    ///
+    /// **Panics** if the slice length is greater than `isize::MAX`.
     fn from(slice: &'a mut Slice) -> Self {
         let xs = slice.as_mut();
         if mem::size_of::<A>() == 0 {
@@ -271,12 +268,11 @@ impl<'a, A, Slice: ?Sized> From<&'a mut Slice> for ArrayViewMut<'a, A, Ix1>
 }
 
 /// Implementation of `ArrayViewMut::from(&mut A)` where `A` is an array.
-///
-/// Create a read-write array view of the array.
 impl<'a, A, S, D> From<&'a mut ArrayBase<S, D>> for ArrayViewMut<'a, A, D>
     where S: DataMut<Elem=A>,
           D: Dimension,
 {
+    /// Create a read-write array view of the array.
     fn from(array: &'a mut ArrayBase<S, D>) -> Self {
         array.view_mut()
     }