[PATCH v2] docs/man: add shutdown reasons to xl (list) man page

["zithro / Cyril Rébert" <slack@rabbit.lu>]

Add the shutdown reasons to the paragraph of "xl list" concerning the
shutdown status.
I have adapted the explanations from the source code :

 - tools/xl/xl_info.c : function "list_domains()", variable
   "shutdown_reason_letters"
 - xen/include/public/sched.h : variable "shed_shutdown_reason"

Suggested-by: Roger Pau Monné <roger.pau@citrix.com>
Signed-off-by: Cyril Rébert / zithro <slack@rabbit.lu>
---
v2:
- apply changes from Anthony and Roger

Questions (unblocking):
 - why a double space between all sentences ?
 - how to get a "simple LF" ? Ie. I want to use <br>, not <p>
   (a simple <Enter> has no effect, a double renders a <p>)
---
 docs/man/xl.1.pod.in | 40 +++++++++++++++++++++++++++++++++++++++-
 1 file changed, 39 insertions(+), 1 deletion(-)

diff --git a/docs/man/xl.1.pod.in b/docs/man/xl.1.pod.in
index bed8393473..d37227ba58 100644
--- a/docs/man/xl.1.pod.in
+++ b/docs/man/xl.1.pod.in
@@ -370,12 +370,50 @@ scheduling by the Xen hypervisor.
 The guest OS has shut down (SCHEDOP_shutdown has been called) but the
 domain is not dying yet.
 
-=item B<c - crashed>
+There are six shutdown reasons, which will be displayed after the "s" : B<-rscwS>.
+
+Note that some states will only be displayed if "on_poweroff=preserve" is set in
+the config file, see L<xl.cfg(5)>).
+
+=over 4
+
+=over 4
+
+=item B<s- : poweroff>
+
+The domain exited normally, it will get destroyed.
+
+=item B<sr : reboot>
+
+The domain will reboot.
+
+=item B<ss : suspend>
+
+The domain is suspended to disk or to RAM. If suspended to disk, the domain will
+get destroyed.
+
+=item B<sc : crash>
 
 The domain has crashed, which is always a violent ending.  Usually
 this state only occurs if the domain has been configured not to
 restart on a crash.  See L<xl.cfg(5)> for more info.
 
+=item B<sw : watchdog>
+
+Restart because watchdog time expired.
+
+=item B<sS : soft_reset>
+
+The domain asked to perform 'soft reset' for it.  The expected behavior
+is to reset internal Xen state for the domain returning it to the point
+where it was created but leaving the domain's memory contents and vCPU
+contexts intact.  This will allow the domain to start over and set up
+all Xen specific interfaces again.
+
+=back
+
+=back
+
 =item B<d - dying>
 
 The domain is in the process of dying, but hasn't completely shut down or
-- 
2.39.2