bugfix dbg-webview without "~a"

racket-webview.rkt

@@ -200,7 +200,7 @@
   (let ((content (file->bytes path)))
     (dbg-webview "path = ~a, number of bytes read: ~a" path (bytes-length content))
     (when (string-suffix? (format "~a" path) "stop.svg")
-      (dbg-webview content))
+      (dbg-webview "~a" content))
     (display content out)))
 
 (define (make-security-token)