Mixed js and html syntax messes up the highlighting

[christian-oudard]

<%
const {page, nav} = locals

function navLink(pageName) {
  if (page == pageName) {
    return `<span>${pageName}</span>`
  } else {
    return `<a href="/${pageName}">${pageName}</a>`
  }
}
%>

In this example, the syntax highlighting breaks on the first < of <span.