fix: add missing final line

On the final line, eval must be called with two arguments: the
expression and the association list.

The final line is missing a closing parenthesis in the original document
to match the initial opening parenthesis.

This commit also adds a missing closing parenthesis on line 10.

eval.lisp

@@ -7,7 +7,7 @@
                    (lambda (e a)
                     (cond ((null a) nil)
                        ((eq e caar a)) (car a)
-                       (t (assoc e (cdr a)))))
+                       (t (assoc e (cdr a))))))
                    e
                    a)))))
         ((atom (car e))
@@ -73,4 +73,5 @@
              a))
             a)))
         ((eq (caar e) (quote label))
-         (eval (cons (caddar e) (cdr e))) a)))))
+         (eval (cons (caddar e) (cdr e))
+                 (cons (cons (cadar e) (car e)) a))))))