vzdump: notes template: mention pool variable in description

The notes template now also supports a {{pool}} variable, which is
replaced with the resource pool the guest is a member of.

Signed-off-by: Michal Fox <me@dualfroz.com>

src/PVE/VZDump/Common.pm

@@ -363,9 +363,9 @@ my $confdesc = {
         type => 'string',
         description => "Template string for generating notes for the backup(s). It can contain"
             . " variables which will be replaced by their values. Currently supported are"
-            . " {{cluster}}, {{guestname}}, {{node}}, and {{vmid}}, but more might be added in the"
+            . " {{cluster}}, {{guestname}}, {{node}}, {{pool}}, and {{vmid}}, but more might be"
-            . " future. Needs to be a single line, newline and backslash need to be escaped as '\\n'"
+            . " added in the future. Needs to be a single line, newline and backslash need to be"
-            . " and '\\\\' respectively.",
+            . " escaped as '\\n' and '\\\\' respectively.",
         requires => 'storage',
         maxLength => 1024,
         optional => 1,