How to use the alex.markdown function in alex

async function processBlob(context, owner, repo, tree_sha, filename, file_sha) {
  const {data: {content: encoded}} = await context.github.gitdata.getBlob({owner, repo, sha: file_sha})
  const decoded = Buffer.from(encoded, 'base64').toString()
  context.log(`Blob (${file_sha}) for https://github.com/${owner}/${repo}/blob/${tree_sha}/${filename} is: %j`, decoded)

  const analysis = alex.markdown(decoded).messages.map(message => {
    const {message: description, ruleId: title, location} = message
    return {
      path: filename,  // The path to the file being annotated.
      start_line: location.start.line, // The start line of the annotation.
      end_line: location.end.line, // The end line of the annotation.
      annotation_level: 'notice', // The level of the annotation. Can be one of notice, warning, or failure.
      message: description, // A short description of the feedback for these lines of code. The maximum size is 64 KB.
      title: title // The title that represents the annotation. The maximum size is 255 characters.
    }
  })

  return analysis
}

buildResults () {
    const results = new Map()

    for (const [filename, contents] of this.contentMap) {
      const res = alex.markdown(contents).messages
      results.set(filename, this.serializeReasons(res))
    }

    return results
  }
}

function checkContent(isRichText, value, config = {}) {
  const { messages } = isRichText
    ? alex.text(documentToPlainTextString(value), config)
    : alex.markdown(value, config);

  return messages;
}