[mail] Update aerc accounts configuration

Update aerc accounts configuration with better notmuch support

mail/aerc/accounts.conf

@@ -1,16 +1,11 @@
 [migadu]
-#
-# Switching back to notmuch (from maildir experiment)
-#
-source    = notmuch:///home/adam/Maildir
-maildir-store = /home/adam/Maildir
-outgoing  = /home/adam/.local/bin/aerc-notmuch-send migadu
-default   = INBOX
-from      = Adam Cooper <adam@theadamcooper.com>
-
-# notmuch does not support the copy-to directive
-# copy-to   = Sent
-check-mail = 4m
-check-mail-cmd = /home/adam/.local/bin/mail-sync.sh
+source             = notmuch:///home/adam/Maildir
+maildir-store      = /home/adam/Maildir
+outgoing           = /usr/sbin/sendmail
+default            = INBOX
+from               = Adam Cooper <adam@theadamcooper.com>
+copy-to            = Sent
+check-mail         = 4m
+check-mail-cmd     = /home/adam/.local/bin/mail-sync.sh
 check-mail-timeout = 20s