Remove space before exclamation point in Doorbell success notification

If we're removing spaces before colons (backend#1412 (closed)), might as well also do it with exclamation points. git grep -IP '\s!(?![=[])' shows that the only occurrence of a space before an exclamation point, something that has not been allowed in English since the 20th century, is here. This terrifying blank character is obviously the worst problem that Arkindex has.

If you feel like bikeshedding even more than I am, feel free to pluck some arguments from this English StackExchange question.