qemu-img-cmds.hx: Update comment that mentions Texinfo

Missed in 3c95fdef94 "Update comments in .hx files that mention
Texinfo".

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20200929075824.1517969-2-armbru@redhat.com>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
1 file changed