docs: Xen improvements

In formatdomain, using 'libxl' and 'xen' is redundant since they now
both refer to the same driver. 'xen' predates 'libxl' and unambiguously
identifies the Xen hypervisor, so drop the use of 'libxl'.

In aclpolkit, the connection URI was erroneously identified as 'libxl'
and the name 'xenlight'. Change the URI to 'xen' and driver name to 'Xen'.
Signed-off-by: NJim Fehlig <jfehlig@suse.com>
Reviewed-by: NDaniel P. Berrangé <berrange@redhat.com>

docs/aclpolkit.html.in

@@ -342,8 +342,8 @@
           <td>interface</td>
         </tr>
         <tr>
-          <td>libxl</td>
-          <td>xenlight</td>
+          <td>xen</td>
+          <td>Xen</td>
         </tr>
         <tr>
           <td>lxc</td>

docs/formatdomain.html.in

@@ -2533,8 +2533,8 @@
             The <code>name</code> attribute selects which timer is
             being modified, and can be one of
             "platform" (currently unsupported),
-            "hpet" (libxl, xen, qemu, lxc), "kvmclock" (qemu),
-            "pit" (qemu), "rtc" (qemu, lxc), "tsc" (libxl, qemu -
+            "hpet" (xen, qemu, lxc), "kvmclock" (qemu),
+            "pit" (qemu), "rtc" (qemu, lxc), "tsc" (xen, qemu -
             <span class="since">since 3.2.0</span>), "hypervclock"
             (qemu - <span class="since">since 1.2.2</span>) or
             "armvtimer" (qemu - <span class="since">since 6.1.0</span>).
@@ -7518,7 +7518,7 @@ qemu-kvm -net nic,model=? /dev/null
         <p>
           You can provide the amount of video memory in kibibytes (blocks of
           1024 bytes) using <code>vram</code>. This is supported only for guest
-          type of "libxl", "vz", "qemu", "vbox", "vmx" and "xen". If no
+          type of "vz", "qemu", "vbox", "vmx" and "xen". If no
           value is provided the default is used. If the size is not a power of
           two it will be rounded to closest one.
         </p>