Merge pull request #402 from jorisvr/fix_doc_vertex

Fix time complexity spec of vertex()

Author: jeremy-murphy

doc/using_adjacency_list.html

@@ -133,7 +133,7 @@ <H4>Time Complexity</H4>
 <PRE>
 vertex()
 </PRE>
-This operation is constant time for <TT>vecS</TT> and  for
+This operation is constant time for <TT>vecS</TT> and <i>O(V)</i> for
 <TT>listS</TT>.
 
 </ul>