function isNodeSupportedLanguage(node) {
    const lang = getLangAttribute(node);
    return !(lang && unsupportedLanguages.includes(lang));
}
Checks whether the node contains a `lang` or `type` attribute with a value corresponding to
a language we cannot format. This might for example be `<template lang="pug">`.
If the node does not contain a `lang` attribute, the result is true.