2.3 Adding new tags

• Create a custom tag via the tag() function:

  customTag <- tag(
    "test",
    list(
      class = "custom",
      p("Custom tag's only child")
    )
  )
  customTag

  <test class="custom">
    <p>Custom tag's only child</p>
  </test>

• Validate if the custom tag follows the HTML standards.