RE: file-cache doc should state that the cache is non-persistent

[Drew Adams]

I said:

    Looking at both the File Name Cache node in the Emacs manual
    and the Lisp source code, I see nothing that indicates whether
    or not the cache is persistent.

    This is an important piece of information. The doc should make
    it clear that the cache is not persistent and that it launches
    `find' each time you use it to find a file.

Sorry; strike the last phrase about `find'. I believe the rest is accurate,
though.