typo in ex2_5

Exercises/ex2_5.md

@@ -206,7 +206,7 @@ into 4 separate `append()` operations.
 
 class RideData(collections.abc.Sequence):
     def __init__(self):
-        # Each value is a list with all of the values (a column)
+        # Each value is a list with all the values (a column)
         self.routes = []
         self.dates = []
         self.daytypes = []