bug#15047: 24.3.50; doc string of `find-listp-find-files' etc.

[Drew Adams]

> > The doc should distinguish between the files _within_ a directory, i.e.,
> > descending into its subdirectories recursively, and the files in a
> > directory, i.e., not including in descendent directories.
> >
> > Pick any terminology you like, but please make it clear.
> >
> > 1. `find-listp-find-files': The doc of does not at all indicate that it
> > in fact searches also subdirectories, recursively.
> 
> Fixed...
> 
> > 2. `find-lisp-find-files-internal': The doc says that
> > "DIRECTORY-PREDICATE is used to decide...", but it does not say how,
> > which is central to the meaning of DIRECTORY-PREDICATE.  Just say that
> > if DIRECTORY-PREDICATE returns non-nil then descend into subdirs etc.
> 
> It's a predicate.  That's what predicates do.

Have you looked at this doc and function?

I had no complaint with what the doc string says about arg
FILE-PREDICATE.  It says that it is a predicate that files
under DIRECTORY need to satisfy, for them to be found.

Things are very different for DIRECTORY-PREDICATE.  What is
it?  What is it applied to?  If you look at the code you will
see that it is applied to a directory, and if it succeeds
the function is called recursively to look for files under
that directory.

That should be explained in the doc: what the predicate is
applied to and what its effect is.