[parse-declarations-devel] [patch] off-by-one in atomic-type-specifier-p; comment typo

Without the first patch, this answers nil:

(build-declarations nil (filter-declaration-env (parse-declarations '((declare (fixnum x y z)))) :affecting '(x)))

With it I get ((type fixnum x)) as I expect.

A potential accuracy improvement for non-built-in types would be to use:

#+clozure (ccl::specifier-type symbol env)

similarly to the #+sbcl case; I will send that along as well if you like.

Also a tiny typo in the comment is patched.