[[[foo]]]

[[[foo]]]: /url


----------

(Document
  (Paragraph
    '['
    '['
    '['
    'foo'
    ']'
    ']'
    ']')
  (Paragraph
    '['
    '['
    '['
    'foo'
    ']'
    ']'
    ']'
    ': /url'))
