Hash table read syntax

[Chong Yidong]

I think there's a problem with the design of the hash table read syntax:

(make-hash-table)
#s(hash-table size 65 test eql rehash-size 1.5 rehash-threshold 0.8 data ())

The plist ought to use `:size', `:test', `:rehash-size', etc., rather
than `size', `test', `rehash-size', etc.  Otherwise, it's inconsistent
with the arguments to `make-hash-table', which uses `:size', `:test',...

I would like to make this change now, before it becomes "official" with
the Emacs 23.2 release.  Any objections?