Use url entities for links between docs

svn path=/head/; revision=21827

en_US.ISO8859-1/books/handbook/introduction/chapter.sgml

@@ -60,7 +60,7 @@
       or the <link linkend="relnotes">current release</link>.  If you
       are interested in contributing something to the Project (code,
       hardware, unmarked bills), see the <ulink
-	url="../../articles/contributing/index.html">Contributing to FreeBSD</ulink> article.</para>
+	url="&url.articles.contributing;/index.html">Contributing to FreeBSD</ulink> article.</para>
 
     <sect2 id="os-overview">
       <title>What Can FreeBSD Do?</title>
@@ -690,7 +690,7 @@
 	process, being literally built from the contributions
 	of hundreds of people around the world, as can be seen from
 	our <ulink
-	url="../../articles/contributors/article.html">list of
+	url="&url.articles.contributors;/article.html">list of
 	contributors</ulink>.  FreeBSD's development infrastructure allow
 	these hundreds of developers to collaborate over the Internet.
 	We are constantly on the lookout for
@@ -777,7 +777,7 @@
 	      ensuring that some large portion of the system works as
 	      advertised.  For a complete list of FreeBSD developers
 	      and their areas of responsibility, please see the <ulink
-	      url="../../articles/contributors/article.html">Contributors
+	      url="&url.articles.contributors;/article.html">Contributors
 	      List</ulink></para>
 
 	    <note>
@@ -809,7 +809,7 @@
               the various FreeBSD mailing lists.</para>
 	  
 	    <para><citetitle><ulink
-	      url="../../articles/contributors/article.html">The
+	      url="&url.articles.contributors;/article.html">The
 	      FreeBSD Contributors List</ulink></citetitle> is a long
 	      and growing one, so why not join it by contributing
 	      something back to FreeBSD today?</para>