Restrict Attribute List for Custom Elements/Web Components

[break-stuff]

There may be instances where the developer doesn't want to or shouldn't see a full list of HTML attributes when working with custom elements/web components. It would be nice to be able to restrict the list of available attributes to those that have been defined in the html.customData configuration or at least promote them to the top of the list.

In this screenshot, the two defined attributes for this component are size and value, which the developer is unaware of because they are buried in this list somewhere.