expander: fix malformed linklet

A linklet generated for deserializing syntax objects shadowed a local
variable, which is not allowed.

racket/src/cs/schemified/expander.scm

@@ -37673,12 +37673,12 @@
                           'let-values
                           (list
                            (list
-                            '(stx)
+                            '(new-stx)
                             (list*
                              'unsafe-vector*-ref
                              syntax-literals-id
                              '(pos))))
-                          '((if stx stx (loop))))))))
+                          '((if new-stx new-stx (loop))))))))
                      '((loop))))))))))))))))))
 (define generate-lazy-syntax-literals-data!
   (lambda (sl_0 mpis_0)

racket/src/expander/compile/header.rkt

@@ -127,9 +127,9 @@
                                    (lambda ()
                                      (begin
                                        (vector-cas! ,syntax-literals-id pos #f stx)
-                                       (let-values ([(stx) (unsafe-vector*-ref ,syntax-literals-id pos)])
-                                         (if stx
-                                             stx
+                                       (let-values ([(new-stx) (unsafe-vector*-ref ,syntax-literals-id pos)])
+                                         (if new-stx
+                                             new-stx
                                              (loop)))))])
                     (loop))))))))))