HtmlFile:test.html
  PsiElement(HTML_DOCUMENT)
    PsiElement(XML_PROLOG)
      PsiElement(XML_DOCTYPE)
        XmlToken:XML_DOCTYPE_START('<!DOCTYPE')
        PsiWhiteSpace(' ')
        XmlToken:XML_NAME('html')
        XmlToken:XML_DOCTYPE_END('>')
      PsiWhiteSpace('\n')