Add the hash documentation to the main BoostBook file.

[SVN r28136]

doc/Jamfile.v2

@@ -9,6 +9,8 @@ boostbook doc : src/boost.xml
      <dependency>../libs/program_options/doc//autodoc.xml 
      <dependency>../libs/algorithm/string/doc//autodoc.xml
      <dependency>../libs/logic/doc//reference.xml
+     <dependency>../libs/functional/hash/doc//hash
+     <implicit-dependency>../libs/functional/hash/doc//hash
      <xsl:param>boost.libraries=../../libs/libraries.htm
 
     ;

doc/src/boost.xml

@@ -302,6 +302,8 @@
      </libraryinfo>
    </library>
 
+   <xi:include href="hash.xml"/>
+
    <library name="Graph" dirname="graph" html-only="1">
      <libraryinfo>
        <author>