Typo fixes

Author: OmkarPathak

pygorithm/data_structures/graph.py

@@ -60,7 +60,7 @@ def get_code(self):
         import inspect
         return inspect.getsource(TopologicalSort)
 
-class CheckCycleDirected(object):
+class CheckCycleDirectedGraph(object):
     def __init__(self):
         self.graph = {}
         self.count = 0
@@ -114,7 +114,7 @@ def get_code(self):
         import inspect
         return inspect.getsource(CheckCycleDirected)
 
-class CheckCycleUndirected(object):
+class CheckCycleUndirectedGraph(object):
     def __init__(self):
         self.graph = {}
         self.count = 0