disable at -> @ replacement when pasting recipient address

MailMate seems to cleverly replace "at" by "@" when pasting into the recipient fields.

However, I found myself unable to circumvent that mechanism in cases where I didn't want it replaced. Example:

"peter at his house" <test@test.com>

This will always convert to

"peter@his house" <test@test.com>

It works if I type it instead of pasting, but there should be a way to disable it.

(It is hard to search for the @ sign here, so I hope this ticket isn't a duplicate.)