Out of office used grey placeholder text, so switching the reply on sent
an empty message. A reply never written now opens with an editable subject
and message in the user's language; the switch stays off while the message
is empty and says "Write a message first", and a reply that is on can't be
saved with its text deleted. Forwarding won't switch on without an address,
and the address field shows while it is off. The page puts the switch
first, then "Reply to" with plain choices, then "From/Until (optional)",
then one message editor with formatting instead of a text box plus a
second "Formatted message (HTML)" box. A message nobody edited is sent as
the server has it. A failed save is no longer retried once at once when
the last change was a click.
Test changes: the forward tests type the address before switching
forwarding on (it no longer switches on without one) and check the new
order and option labels; the HTML-body and template tests use the one
editor instead of the text box and HTML switch, which are gone. The
search index names the new rows.