Update transfer.alert.yaml

Looks like the notes are missing (forgotten?) here. Used/Copied the notes from task.transfer.alert.yaml and replaced "task" with "ticket".

include/i18n/en_US/templates/email/transfer.alert.yaml

@@ -7,7 +7,8 @@
 #
 ---
 notes: |
-
+    Sent to agents when a ticket is transfered to a department to which
+    they are a member.
 subject: |
     Ticket #%{ticket.number} transfer - %{ticket.dept.name}
 body: |