Make #@n always read as a quotation of the nth hashed object.

Make #@n always read as a quotation of the nth hashed object.

Previously, #@n sometimes read as the nth hashed object, and
sometimes read as a quotation of it.  The advantage of the old
behaviour is that non-scode objects could be mentioned inside
quotations with #@n.  Personally, most of the time I referred to
non-scode objects inside quotations with #@n was as '#@n to work
around the problems this fixes:

(lambda (x) x)
;Value 12: #[compound-procedure 12]

(#@12 0)
;The object #[compound-procedure 12], passed as an argument to make-combination, is not an operator expression.

(list 1 2 3)
;Value 18: (1 2 3)

(pp #@18)
;The object 1 is not applicable.