- fix formatting for SourceForge, and point out FreeBSD site to check

for ports

Differential Revision:	https://reviews.freebsd.org/D1156
Approved by:	wblock (mentor)

en_US.ISO8859-1/books/handbook/ports/chapter.xml

@@ -246,10 +246,11 @@
 
 	<para>If finding a particular application becomes challenging, try
 	  searching a site like <link
-	    xlink:href="http://www.sourceforge.net/">SourceForge.net</link>,
-	  or <link xlink:href="http://www.github.com/">GitHub.com</link>,
-	  then check back at the &os; site to see if the application has been
-	  ported.</para>
+	    xlink:href="http://www.sourceforge.net/">SourceForge.net</link>
+	  or <link xlink:href="http://www.github.com/">GitHub.com</link>
+	  then check back at the <link
+	    xlink:href="&url.base;/ports/index.html">&os; site</link> to see
+	  if the application has been ported.</para>
       </listitem>
 
       <listitem>