$ gem install foo
 $ gem --version
>>>
Document
  { docMeta =
      Meta
        { docTitle = []
        , docTitleAttributes = Nothing
        , docAuthors = []
        , docRevision = Nothing
        , docAttributes = fromList [ ( "sectids" , "" ) ]
        }
  , docBlocks =
      [ Block
          mempty
          Nothing
          (LiteralBlock "$ gem install foo\n$ gem --version\n")
      ]
  }