Clarify biconnected components description (#303)

Two distinct paths is a very weak statement (as having overlapping paths which differ by just one edge/node are distinct).  Internally disjoint is a much more apt description.

Author: JJCUBER

content/graph/BiconnectedComponents.h

@@ -5,9 +5,9 @@
  * Source: folklore
  * Description: Finds all biconnected components in an undirected graph, and
  *  runs a callback for the edges in each. In a biconnected component there
- *  are at least two distinct paths between any two nodes. Note that a node can
- *  be in several components. An edge which is not in a component is a bridge,
- *  i.e., not part of any cycle.
+ *  are at least two internally disjoint paths between any two nodes (a cycle
+ *  exists through them). Note that a node can be in several components. An
+ *  edge which is not in a component is a bridge, i.e., not part of any cycle.
  * Usage:
  *  int eid = 0; ed.resize(N);
  *  for each edge (a,b) {