- Fix the description of what maintainer-update really is

Pointed out by:	Boris Samorodov <bsam@ipt.ru>

en_US.ISO8859-1/books/porters-handbook/book.sgml

@@ -6754,8 +6754,7 @@ as .putsy.conf and edit it.</programlisting>
 
       <para> The best way to
 	send us the diff is by including it via &man.send-pr.1; (category
-	<literal>ports</literal>).  If you are volunteering to maintain the
-	port,
+	<literal>ports</literal>).  If you are maintaining the port,
 	be sure to put <literal>[maintainer update]</literal> at the beginning
 	of your synopsis line and set the <quote>Class</quote> of your PR
 	to <literal>maintainer-update</literal>.  Otherwise, the