Update documentation

doc/hash/tutorial.adoc

@@ -1,11 +1,23 @@
+////
+Copyright 2005-2008 Daniel James
+Copyright 2022 Christian Mazakas
+Copyright 2022 Peter Dimov
+Distributed under the Boost Software License, Version 1.0.
+https://www.boost.org/LICENSE_1_0.txt
+////
+
 [#tutorial]
 = Tutorial
-
 :idprefix: tutorial_
 
-When using a hash index with link:../../../multi_index/index.html[Boost.MultiIndex], you don't need to do anything to use `boost::hash` as it uses it by default. To find out how to use a user-defined type, read the <<custom,section on extending boost::hash for a custom data type>>.
+When using a Boost container such as
+link:../../../unordered/index.html[Boost.Unordered], you don't need to do
+anything to use `boost::hash` as it's the default. To find out how to use
+a user-defined type, read the <<user,section on extending boost::hash
+for user types>>.
 
-If your standard library supplies its own implementation of the unordered associative containers and you wish to use `boost::hash`, just use an extra template parameter:
+If you wish to use `boost::hash` with the standard unordered associative
+containers, pass it as a template parameter:
 
 [source]
 ----
@@ -27,12 +39,24 @@ To use `boost::hash` directly, create an instance and call it as a function:
 int main()
 {
     boost::hash<std::string> string_hash;
-
     std::size_t h = string_hash("Hash me");
 }
 ----
 
-For an example of generic use, here is a function to generate a vector containing the hashes of the elements of a container:
+or alternatively:
+
+[source]
+----
+#include <boost/container_hash/hash.hpp>
+
+int main()
+{
+    std::size_t h = boost::hash<std::string>()("Hash me");
+}
+----
+
+For an example of generic use, here is a function to generate a vector
+containing the hashes of the elements of a container:
 
 [source]
 ----