Fix the syntactic context.

https://racket.discourse.group/t/wrap-a-macro-injecting-bindings-in-another-macro/1406/2

utils.rkt

@@ -126,7 +126,7 @@
      (define colons (collect-colons (syntax->datum stx)))
      (define bindings (for/list ([key colons])
                         `[,key (hash-ref ,#'ht ',(strip-colon key))]))
-     (with-syntax ([bindings-stx (datum->syntax stx bindings)])
+     (with-syntax ([bindings-stx (datum->syntax #'ht bindings)])
        #'(let bindings-stx body))]))
 
 (module+ test