docs: Fix typo

It used "&lt" for ">", reported by Kyla Zhang <weizhan@redhat.com>

docs/formatdomain.html.in

@@ -1096,9 +1096,9 @@
     </disk>
     <disk type='block' device='lun'>
       <driver name='qemu' type='raw'/>
-      <source dev='/dev/sda'/<
-      <target dev='sda' bus='scsi'/<
-      <address type='drive' controller='0' bus='0' target='3' unit='0'/<
+      <source dev='/dev/sda'/>
+      <target dev='sda' bus='scsi'/>
+      <address type='drive' controller='0' bus='0' target='3' unit='0'/>
     </disk>
   </devices>
   ...</pre>