Re: doco hash tables

[Kevin Ryde]

I made these changes,

        * scheme-compound.texi (Hash Table Reference): Collect up groups of
        functions to avoid duplication.  Revise notes on hashx functions and
        on vector implementation.  In make-hash-table, size is now optional.
        Add hash-map and hash-for-each.

What can be said about the new resizing stuff and the initial size in
make-hash-table?  Is the initial size a permanent minimum, or just a
hint?  (I couldn't quite tell from the code.)