Use man entity for sysctl(8).

svn path=/head/; revision=14589

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

@@ -822,7 +822,7 @@ passwd: done</screen>
 	    running.  This includes foreground and background processes
 	    alike.  For obvious reasons, this may not be larger than the
 	    system limit specified by the <varname>kern.maxproc</varname>
-	    <command>sysctl</command>.  Also note that setting this 
+	    &man.sysctl.8;.  Also note that setting this 
 	    too small may hinder a
 	    user's productivity: it is often useful to be logged in
 	    multiple times or execute pipelines.  Some tasks, such as
@@ -879,7 +879,7 @@ passwd: done</screen>
 	    open.  In FreeBSD, files are also used to represent sockets and
 	    IPC channels; thus, be careful not to set this too low.  The
 	    system-wide limit for this is defined by the
-	    <varname>kern.maxfiles</varname> <command>sysctl</command>.</para>
+	    <varname>kern.maxfiles</varname> &man.sysctl.8;.</para>
 	</listitem>
       </varlistentry>