Fix method visibility in JsonApiExtra

Author: yenshirak

gem/lib/pagy/extras/jsonapi.rb

@@ -18,10 +18,12 @@ def initialize(value)
 
     # Module overriding Backend
     module BackendOverride
-      private
-
       include UrlHelpers
 
+      private(*UrlHelpers.instance_methods)
+
+      private
+
       # Return the jsonapi links
       def pagy_jsonapi_links(pagy, **opts)
         if defined?(::Pagy::Keyset) && pagy.is_a?(Keyset)