src/language-markdown/print-preprocess.js/mergeContinuousTexts
function mergeContinuousTexts(ast) {
  return mergeChildren(
    ast,
    (prevNode, node) => prevNode.type === "text" && node.type === "text",
    (prevNode, node) => ({
      type: "text",
      value: prevNode.value + node.value,
      position: {
        start: prevNode.position.start,
        end: node.position.end,
      },
    })
  );
}