message: Correction of typo in barycenter_user
diff: .. To get rid of WARNING: document isn't included in any toctree
  -Wasserstein distance user manual
  +Barycenter user manual
  ================================
  Definition
  ----------
  -.. include:: wasserstein_distance_sum.inc
  +.. include:: barycenter_sum.inc
  This implementation is based on ideas from "Frechet means for distribution of persistence diagrams", Turner et al. 2014.
  