[Minor] Ability to disable all e-mail notifications

Currently, I have the ability to disable e-mail notifications only per the type of the notification (“New Phrase”, “New Comments”, …).
It would be good if the user would have the option to disable all types of the e-mail notifications with a click of one button instead of disabling them one by one.

Something like this (but the buttons would be in the center besides each oterh):

Yes, definitely improvement. Noting this down. Thanks!