Rails 5 compatibility: url query params

As "params" is now an ActionController::Parameters and not an Hash, in
rails 5, the method that set query parameters in url should be fixed, to
take this change in consideration.

lib/will_paginate/view_helpers/link_renderer.rb

@@ -119,7 +119,7 @@ def symbolized_update(target, other)
           key = key.to_sym
           existing = target[key]
 
-          if value.is_a?(Hash) and (existing.is_a?(Hash) or existing.nil?)
+          if (value.is_a?(ActionController::Parameters) or value.is_a?(Hash)) and (existing.is_a?(Hash) or existing.nil?)
             symbolized_update(existing || (target[key] = {}), value)
           else
             target[key] = value