Javascript error when loading CustomDatas in foreign languages (french for example)

In french
Create a new multiple-valued custom dataset for a contact record, go to a contact's record, in your custom tab, the datas are loaded through an ajax request which raises a javascript failure.

The error comes from a non js-escaped string, since the french translation adds " ' ", the javascipt message results in an error.
adding a escape="js" solves the problem. (should be used for all javascript translated messages.
See attached patch