Add reference to JavaScript functionality

Since the functionality of `dominate.util.raw` is practically the same as the [`element.innerHTML` in JavaScript](https://developer.mozilla.org/en-US/docs/Web/API/Element/innerHTML), and this is very widespread in the "HTML community", I think it is a good idea to provide this reference in the documentation for people doing `ctrl`+`f`←`innerhtml` in their browsers looking for this functionality.