Pass user account action to email

It's better if recipients know what the user account action was (insert, update).

I changed user_register_notify_user(), case 'update' to include the action:

user_register_notify_setup_email($edit, $account, 'update');

and

user_register_notify_setup_email(&$edit, &$account, $action = 'insert')

and
$variables to include

'!action' => $action == 'insert'? 'create' : 'update',

The !action placeholder can then be included in the email template.