code: function fixAllLinks(htmlFiles) {
    const writePromises = [];
    htmlFiles.forEach(file => {
      // Update links in each html file to match flattened file structure.
      writePromises.push(fixLinks(`${docPath}/${file}.html`));
    });
    return Promise.all(writePromises);
  }
docs: Fix all links in generated files to other generated files to point to top
  level of generated docs dir.
  
  @param {Array} htmlFiles List of html files found in generated dir.