Update "Video - Nico Nico Douga" Extractor

* Rename "Video - Nico Nico Douga" to "Video - Nicovideo"

via https://github.com/Constellation/taberareloo/blob/1a6e47f03e8a93ace56a7fece05fd214123893ce/src/lib/extractors.js#L1225
    https://github.com/Constellation/taberareloo/pull/194