MFH: r554666

mail/rainloop: fix position of double quote

This rode in back in r541184 (2020/07/04) and is clearly bogus, but somehow
hasn't been an issue until now. Move the quotation mark outside of the right
brace.

Approved by: portmgr (implicit, just-fix-it)

Approved by: ports-secteam (implicit, just-fix-it)