Remove repeated object class identifiers and array identifiers from output

[ajberkley]

Previously:

(defstruct blarg)
(conspack:defencoding blarg)
(conspack:explain
	  (conspack:tracking-refs ()
	   (conspack:encode (list (make-blarg) (make-blarg)
                                  (make-array '(1 1)) (make-array '(1 1))))))
((:LIST 5
  ((:TMAP 0 ((:SYMBOL BLARG))) (:TMAP 0 ((:SYMBOL BLARG)))
   (:TMAP 3
    ((:SYMBOL ARRAY) (:TAG 0 (:SYMBOL :DIMENSIONS))
     (:LIST 3 ((:NUMBER :INT8 1) (:NUMBER :INT8 1) (:BOOLEAN NIL)))
     (:TAG 1 (:SYMBOL :ELEMENT-TYPE)) (:BOOLEAN T) (:TAG 2 (:SYMBOL :CONTENT))
     (:VECTOR 1 ((:NUMBER :INT8 0)))
     (:TMAP 3
      ((:SYMBOL ARRAY) (:REF 0)
       (:LIST 3 ((:NUMBER :INT8 1) (:NUMBER :INT8 1) (:BOOLEAN NIL))) (:REF 1)
       (:BOOLEAN T) (:REF 2) (:VECTOR 1 ((:NUMBER :INT8 0)))))
     (:BOOLEAN NIL) END-OF-FILE))
   END-OF-FILE))
 END-OF-FILE)

Notice the repeated :SYMBOL ARRAY and :SYMBOL BLARG

After fix:
((:LIST 5
  ((:TMAP 0 ((:TAG 0 (:SYMBOL BLARG)) (:TMAP 0 ((:REF 0)))))
   (:TMAP 3
    ((:TAG 1 (:SYMBOL ARRAY)) (:TAG 2 (:SYMBOL :DIMENSIONS))
     (:LIST 3 ((:NUMBER :INT8 1) (:NUMBER :INT8 1) (:BOOLEAN NIL)))
     (:TAG 3 (:SYMBOL :ELEMENT-TYPE)) (:BOOLEAN T) (:TAG 4 (:SYMBOL :CONTENT))
     (:VECTOR 1 ((:NUMBER :INT8 0)))
     (:TMAP 3
      ((:REF 1) (:REF 2)
       (:LIST 3 ((:NUMBER :INT8 1) (:NUMBER :INT8 1) (:BOOLEAN NIL))) (:REF 3)
       (:BOOLEAN T) (:REF 4) (:VECTOR 1 ((:NUMBER :INT8 0)))))
     (:BOOLEAN NIL) END-OF-FILE))
   END-OF-FILE))
 END-OF-FILE)