activation url shortcode not working properly

Hi,

Great plugin, but the activation url shortcode is not correctly adding the link to the email.

In my case it is missing the : in the url, example:

https//www.airsoftcompetition.com?activation_key=df7691a6dfc4cde1c585540a317064a9&user_verification_action=email_verification&_wpnonce=f9782b9542

and therefor users cannot register.

It looks a simple fix in the plugin, but I cannot find the right file in the editor.