Correct commented b64encode code in multiselect

The arguments to b64encode need to be bytes, not a direct string. As @plocket noticed, this is corrected in the multiselect_demo.yml, but not in multiselect.yml.

docassemble/ALToolbox/data/questions/multiselect.yml

@@ -19,7 +19,7 @@ comment: |
   script: |
     <script type="text/javascript">
         $(document).ready(function() {
-            $("#${ base64.b64encode("input_name") }").multiselect({enableCaseInsensitiveFiltering: true, inheritClass: true});
+            $("#${ base64.b64encode("input_name".encode()) }").multiselect({enableCaseInsensitiveFiltering: true, inheritClass: true});
         });
     </script>
     
@@ -28,4 +28,4 @@ comment: |
   
   https://davidstutz.github.io/bootstrap-multiselect/
   
-  Forked as of 11/18/2021, with changes to make compatible with Bootstrap 5
+  Forked as of 11/18/2021, with changes to make compatible with Bootstrap 5