doc string of insert-default-directory is unclear

[Drew Adams]

Don't ask me why it's unclear to me, if it's clear to you. In that
case, just take it that at least one user finds this unclear.
 
In previous releases, the doc string said only what its first line
says. The rest was presumably added in Emacs 22 to clarify the meaning
and use. But I find it totally confusing.
 
In particular, the second sentence is not clear, I think:
 
 "If the initial minibuffer contents are non-empty,
  you can usually request a default filename by typing
  RETURN without editing."
 
Please consider rephrasing the entire doc string. A good starting
point could be to explain the significance of the initial contents
being non-empty. The doc string should give you an idea when you might
want to bind this to nil or non-nil. That is not the case now, IMO.
 

In GNU Emacs 22.1.1 (i386-mingw-nt5.1.2600)
 of 2007-06-02 on RELEASE
Windowing system distributor `Microsoft Corp.', version 5.1.2600
configured using `configure --with-gcc (3.4) --cflags -Ic:/gnuwin32/include'