Link to Wikipedia to explain what C3 is

Author: zoffixznet

doc/Language/classtut.pod6

@@ -564,9 +564,10 @@ L<MOP|/type/Metamodel::ClassHOW#method_can>.
 
 As mentioned before, a class can inherit from multiple classes.  When a
 class inherits from multiple classes the dispatcher knows to look at both
-classes when looking up a method to search for.  Perl 6 uses the C3
-algorithm to linearize multiple inheritance hierarchies, which is
-better than depth-first search for handling multiple inheritance.
+classes when looking up a method to search for.  Perl 6 uses the L<C3
+algorithm|https://en.wikipedia.org/wiki/C3_linearization> to linearize
+multiple inheritance hierarchies, which is better than depth-first search
+for handling multiple inheritance.
 
     =begin code :skip-test
     class GeekCook is Programmer is Cook {