Add revision history

doc/smart_ptr.adoc

@@ -19,6 +19,8 @@ Greg Colvin, Beman Dawes, Peter Dimov, Glen Fernandes
 
 include::smart_ptr/introduction.adoc[]
 
+include::smart_ptr/changelog.adoc[]
+
 include::smart_ptr/scoped_ptr.adoc[]
 
 include::smart_ptr/scoped_array.adoc[]

doc/smart_ptr/changelog.adoc

@@ -0,0 +1,19 @@
+////
+Copyright 2019 Peter Dimov
+
+Distributed under the Boost Software License, Version 1.0.
+
+See accompanying file LICENSE_1_0.txt or copy at
+http://www.boost.org/LICENSE_1_0.txt
+////
+
+[#changelog]
+# Revision History
+:toc:
+:toc-title:
+:idprefix: changelog_
+
+## Changes in 1.71.0
+
+* Added aliasing constructors to `weak_ptr`
+* Added `weak_ptr<T>::empty()`

doc/smart_ptr/introduction.adoc

@@ -11,7 +11,9 @@ http://www.boost.org/LICENSE_1_0.txt
 
 [#introduction]
 # Introduction
-:idprefix: intro
+:toc:
+:toc-title:
+:idprefix: intro_
 
 Smart pointers are objects which store pointers to dynamically allocated (heap) objects.
 They behave much like built-in {cpp} pointers except that they automatically delete the object