improve documentation and fix merge conflicts

Author: dcoudert

src/sage/graphs/generic_graph.py

@@ -244,7 +244,8 @@
     :meth:`~GenericGraph.blocks_and_cut_vertices` | Compute the blocks and cut vertices of the graph.
     :meth:`~GenericGraph.blocks_and_cuts_tree` | Compute the blocks-and-cuts tree of the graph.
     :meth:`~GenericGraph.is_cut_edge` | Return ``True`` if the input edge is a cut-edge or a bridge.
-    :meth:`~GenericGraph.is_cut_vertex` | Return ``True`` if the input vertex is a cut-vertex.
+    :meth:`~GenericGraph.is_cut_vertex` | Check whether the input vertex is a cut-vertex.
+    :meth:`~GenericGraph.is_vertex_cut` | Check whether ``cut`` is a vertex cut of ``G``.
     :meth:`~GenericGraph.edge_cut` | Return a minimum edge cut between vertices `s` and `t`
     :meth:`~GenericGraph.vertex_cut` | Return a minimum vertex cut between non-adjacent vertices `s` and `t`
     :meth:`~GenericGraph.flow` | Return a maximum flow in the graph from ``x`` to ``y``