Enable explicit mailbox operation again
Enable explicit mailbox operation again

Due to the bug, that is fixed by this commit, zsh-am only supported
stdin-fed mailboxes. Meh.

Signed-off-by: Frank Terbeck <d352dbdf6170085acaf7ed62197a4de1452a0073@bewatermyfriend.org>

ft/zsh-am,ft/zsh-am