When a maildir is synchronized by an external process while aerc is
running (e.g. mbsync), some emails may be moved out of "new" to "cur" or
completely deleted.
These deletions are ignored and aerc may assume these messages are still
here, leading to errors.
Take file deletions into account. Also, add "cur" to the watched
folders since these can be modified as well.
Signed-off-by: Robin Jarry <robin@jarry.cc>
f4d3c8fc77