syntax highlighting alternative front matter formats in vscode

[mehulkar]

If I have a template.hbs that looks like this:

---js
{
  layout: 'base.hbs',
  title: function() {
    return this.item.titem;
  }
}
---

<div>some handlebars stuff</html>

how do I get it to syntax highlight properly in vscode? the html/hbs doesn't syntax highlight correctly:

if I don't use the ---js style frontmatter, it works ok though. Is there a extension I can use? The jstl one shows up when I search for 11ty and it seems to work, but also don't want to configure jstl as the language for hbs file, because of this specialized scenario.

Pretty small / unimportant question, but wasn't sure where else to ask!