code: function checkForMissingFilesAndFixFilenameCase() {
    // Get filenames from toc.yaml.
    const filenames = tocText
      .split('\n')
      .filter(line => line.includes('path:'))
      .map(line => line.split(devsitePath)[1]);
    // Logs warning to console if a file from TOC is not found.
    const fileCheckPromises = filenames.map(filename => {
      // Warns if file does not exist, fixes filename case if it does.
      // Preferred filename for devsite should be capitalized and taken from
      // toc.yaml.
      const tocFilePath = `${docPath}/${filename}.html`;
      // Generated filename from Typedoc will be lowercase.
      const generatedFilePath = `${docPath}/${filename.toLowerCase()}.html`;
      return fs.exists(generatedFilePath).then(exists => {
        if (exists) {
          // Store in a lookup table for link fixing.
          lowerToUpperLookup[
            `${filename.toLowerCase()}.html`
          ] = `${filename}.html`;
          return fs.rename(generatedFilePath, tocFilePath);
        } else {
          console.warn(
            `Missing file: ${filename}.html requested ` +
              `in toc.yaml but not found in ${docPath}`
          );
        }
      });
    });
    return Promise.all(fileCheckPromises).then(() => filenames);
  }
docs: Checks to see if any files listed in toc.yaml were not generated.
  If files exist, fixes filename case to match toc.yaml version.