doc/man: Align list of viridian default enlightenments with libxl

The stimer enlightment was removed from the defaults list in commit
e83077a3d1 ("libxl: don't enable synthetic timers by default") but the
corresponding docs change was not made.  Removing from docs as enabling the
enlightenment will hang Windows 10 guests.

Fixes: e83077a3d1 ("libxl: don't enable synthetic timers by default")
Signed-off-by: James Dingwall <james@dingwall.me.uk>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
master commit: d510f9c143
master date: 2025-11-10 16:56:03 +0000

docs/man/xl.cfg.5.pod.in

@@ -2461,7 +2461,7 @@ guests effectively allowing vCPU hotplug.
 
 This is a special value that enables the default set of groups, which
 is currently the B<base>, B<freq>, B<time_ref_count>, B<apic_assist>,
-B<crash_ctl>, B<stimer>, B<no_vp_limit> and B<cpu_hotplug> groups.
+B<crash_ctl>, B<no_vp_limit> and B<cpu_hotplug> groups.
 
 =item B<all>