Use `placeholder` attribute on input elements for placeholder text (instead of `value` attribute) about chosen

[juanolalla]

While this is fixed in Chosen, here is an external solution I developed for my project:

      // Set placeholder instead of value for chosen select data-placeholder.
      // @see https://github.com/harvesthq/chosen/issues/3133
      $('select').on('chosen:ready', function (e) {
        var placeholder = $(e.target).attr('data-placeholder');
        if (placeholder) {
          var input = $(e.target).next('.chosen-container').find('.chosen-search-input');
          input.attr('placeholder', placeholder);
          input.val('');
          input.removeAttr('value');
        }
      });