bug#18694: 25.0.50; `ibuffer(-saved)-filter-groups', `ibuffer-saved-filters'

[Drew Adams]

Besides which, the doc string of `ibuffer-filtering-qualifiers'
seems to be plain wrong, in saying that its form is
(SYMBOL . QUALIFIER), even though QUALIFIER is unfortunately
undefined.

If you plug (SYMBOL . QUALIFIER) in for the QUALIFIERS of
`ibuffer-saved-filters' (which supposedly has the same form as
`ibuffer-filtering-qualifiers') then `ibuffer-saved-filters' should
have this form:
(("STRING" (SYMBOL . QUALIFIER))
 ("STRING" (SYMBOL . QUALIFIER))...)

But that does not match the default value of `ibuffer-saved-filters',
which is more like this:
(("STRING" ((or (SYMBOL . QUALIFIER) (SYMBOL . QUALIFIER)...)))
 ("STRING" ((or (SYMBOL . QUALIFIER) (SYMBOL . QUALIFIER)...))))

And even if it is a mistake to say, in the doc of
`ibuffer-filtering-qualifiers', that it has the form
(SYMBOL . QUALIFIER), and that what is really meant is that it
is a *list of conses* (SYMBOL . QUALIFIER), the doc of
`ibuffer-saved-filters' still does not match its default value.

If we plug a list ((SYMBOL . QUALIFIER) (SYMBOL . QUALIFIER) ...)
in for the QUALIFIERS of `ibuffer-saved-filters' then that option
should have this form:

(("STRING" ((SYMBOL . QUALIFIER) (SYMBOL . QUALIFIER) ...))
 ("STRING" ((SYMBOL . QUALIFIER) (SYMBOL . QUALIFIER) ...))
 ...)

But the default value has that pesky `(or ...)':

(("STRING" ((or (SYMBOL . QUALIFIER) (SYMBOL . QUALIFIER)...)))
            ^^^
 ("STRING" ((or (SYMBOL . QUALIFIER) (SYMBOL . QUALIFIER)...))))
            ^^^

Something is wrong somewhere.  Perhaps more than one something.