src/language-handlebars/parser-glimmer.js/calculateOffset
function addOffset(text) {
  const lines = new LinesAndColumns(text);
  const calculateOffset = ({ line, column }) =>
    lines.indexForLocation({ line: line - 1, column });
  return (/* options*/) => ({
    name: "addOffset",
    visitor: {
      All(node) {
        const { start, end } = node.loc;
        start.offset = calculateOffset(start);
        end.offset = calculateOffset(end);
      },
    },
  });
}