Fix and update documentation and release notes

doc/changes.qbk

@@ -25,6 +25,12 @@
 * Added [link core.serialization `boost/core/serialization.hpp`], a collection of primitives allowing libraries to
   implement Boost.Serialization support for their types without including a Serialization header and thereby making
   their libraries depend on Serialization.
+* Added [link core.data `boost::data`], an implementation of `std::data`.
+* Added [link core.size `boost::size`], an implementation of `std::size`.
+* Updated `boost::span` to use `boost::data` which adds support for range
+  construction from an `std::initializer_list`.
+* Added [link core.identity `boost::identity`], an implementation of
+  `std::identity`.
 
 [endsect]
 

doc/data.qbk

@@ -50,10 +50,10 @@ data(std::initializer_list<T> l) noexcept;
 [variablelist
 [[`template<class C> constexpr auto data(C& c) noexcept(noexcept(c.data())) ->
 decltype(c.data());`]
-[Returns `c.begin()`.]]
+[Returns `c.data()`.]]
 [[`template<class C> constexpr auto data(const C& c)
 noexcept(noexcept(c.data())) -> decltype(c.data());`]
-[Returns `c.begin()`.]]
+[Returns `c.data()`.]]
 [[`template<class T, std::size_t N> constexpr T* data(T(&a)[N]) noexcept;`]
 [Returns `a`.]]
 [[`template<class T> constexpr const T* data(std::initializer_list<T> l)

doc/span.qbk

@@ -227,13 +227,13 @@ constexpr span(R&& r);`]
 [`remove_cvref_t<R>` is not a specialization of `span`,]
 [`remove_cvref_t<R>` is not a specialization of `array`,]
 [`is_array_v<remove_cvref_t<R>>` is `false`,]
-[`r.data()` is well-formed and
+[`data(r)` is well-formed and
 `is_convertible_v<remove_pointer_t<iterator_t<R> >(*)[],
 T(*)[]>` is `true`, and]
 [`r.size()` is well-formed and
 `is_convertible_v<decltype(declval<R&>().size()), size_t>` is `true`.]]]]
-[[Effects][Constructs a `span` with data `r.data()` and size `r.size()`.]]
-[[Throws][What and when r.data() and r.size() throw.]]]]]
+[[Effects][Constructs a `span` with data `data(r)` and size `r.size()`.]]
+[[Throws][What and when data(r) and r.size() throw.]]]]]
 [[`explicit(E != dynamic_extent && N == dynamic_extent)
 template<class U, std::size_t N>
 constexpr span(const span<U, N>& s) noexcept;`]