Add /tmp to the list of standart mount points

svn path=/head/; revision=23336

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

@@ -588,7 +588,7 @@ total 530
 
     <para>A mount point is a directory where additional file systems can
       be grafted onto the root file system.  Standard mount points include
-      <filename>/usr</filename>, <filename>/var</filename>,
+      <filename>/usr</filename>, <filename>/var</filename>, <filename>/tmp</filename>,
       <filename>/mnt</filename>, and <filename>/cdrom</filename>.  These
       directories are usually referenced to entries in the file
       <filename>/etc/fstab</filename>.  <filename>/etc/fstab</filename> is