message: Doc review: no duplicated edges
diff: @@ -317,8 +317,7 @@ class Flag_complex_edge_collapser {
  * can be directed_tag (the fastest, the least RAM use), undirected_tag or even
  * bidirected_tag.
  *
  - * If an edge appears with multiplicity, the function will arbitrarily pick one representative to read the filtration
  - * value.
  + * It is required to have no duplicated edges in the graph.
  *
  * `Gudhi::Proximity_graph<Flag_complex_edge_collapser>` is a good candidate for OneSkeletonGraph.
  */
  