bug#2473: usability issues on emacs's describe-mode

[Richard M Stallman <rms@gnu.org>]

    I see a 3rd way: make the buffer present an expandable list of modes,
    starting with just 2 items: the current major modes and "minor modes",
    e.g. similar to what we do in Speedbar, or maybe in Outline Mode
    (under "Hide Sublevels").  In ASCII art:

      + Major Mode: RMAIL Mode
      + Minor Modes

Using hiding is a good idea -- thanks.

I think that partcular way would be inconvenient.  Specifically, it
would be a hassle to initially hide the major mode documentation.
That is what users most often want to see; making them type a command
to expose it would be a gratuitous hassle.

So I suggest putting the partly-hidden minor mode list first,
followed by the totally visible major mode documentation.