RE: dabbrev-completion doc string

[Drew Adams]

       2. nil is the default value. Why do we _not_ recompute the list of
       completions systematically?

    As I pointed out yesterday, that seems to be what actually happens
    with the current code.  (Unless I am misunderstanding something.)
    `dabbrev-completion' contains an `if' whose long and complex condition
    always returns nil.  Hence, the else part of the `if' is _always_
    executed, meaning that the list is _always_ recomputed.

    Of course, if we believe that the actual behavior is OK, we should
    simplify the `dabbrev-completion' code and get rid of the `if'.

    The incorrect last paragraph of the docstring should then, of course,
    be removed.

Yes, I meant to say what you said.

That is, the doc string seems to be incorrect wrt the behavior: nil means to
search the current buffer only; it does not mean to not recompute the
completions. I'm fine with keeping the current (always recompute) behavior
and correcting the doc string wrt nil.