* Text::Dokuwiki::Render : add default list level

lib/Text/Dokuwiki/Render.pm

@@ -6,7 +6,9 @@ use utf8;
 
 sub new {
   my ($class) = @_;
-  my $self = {};
+  my $self = {
+    list_depth => 0,
+  };
 
   return bless($self, $class);
 }