fixing some bugs

in macro-unwind.rkt:
- in unwind-mz-let, last line, ",label" should just be "label" (no unquote)

in reconstruct.rkt
- in reconstruct-completed-define, last line, arg to attach-info should be a
quasisyntax (#`), not syntax (#')

collects/stepper/private/macro-unwind.rkt

@@ -220,7 +220,7 @@
         (label ([(var ...) rhs] ...) . bodies)
         (with-syntax ([(rhs2 ...) (map (lambda (rhs) (unwind rhs settings)) (syntax->list #'(rhs ...)))]
                       [new-bodies (map (lambda (body) (unwind body settings)) (syntax->list #'bodies))])
-          #`(,label ([(var ...) rhs2] ...) . new-bodies))]))
+          #`(label ([(var ...) rhs2] ...) . new-bodies))]))
    
    (define (unwind-local stx settings)
      (kernel-syntax-case stx #f

collects/stepper/private/reconstruct.rkt

@@ -682,7 +682,7 @@
                             vars)])
       (if (= (length recon-vals) 1)
           (attach-info #`(define-values #,vars #,(car recon-vals)) exp)
-          (attach-info #'(define-values #,vars (values #,@recon-vals)) exp))))
+          (attach-info #`(define-values #,vars (values #,@recon-vals)) exp))))