docs: fix some typos in examples

As detected in https://bugzilla.redhat.com/show_bug.cgi?id=887187

* docs/formatdomain.html.in: Fix XML typos.

docs/formatdomain.html.in

@@ -1048,7 +1048,7 @@
     <hap/>
     <privnet/>
     <hyperv>
-      <relaxed state='on'>
+      <relaxed state='on'/>
     </hyperv>
 
   </features>
@@ -2584,7 +2584,7 @@
     </interface>
     <interface type='bridge'>
       <source bridge='ovsbr'/>
-      <virtualport type='openvswitch'/>
+      <virtualport type='openvswitch'>
         <parameters profileid='menial' interfaceid='09b11c53-8b5c-4eeb-8f00-d84eaa0aaa4f'/>
       </virtualport>
     </interface>
@@ -3871,7 +3871,7 @@ qemu-kvm -net nic,model=? /dev/null
     <serial type="dev">
       <source path="/dev/ttyS0"/>
       <target port="1"/>
-  </serial>
+    </serial>
   </devices>
   ...</pre>