Fix scheduler docs link.

contributors/design-proposals/scheduler_extender.md

@@ -3,7 +3,7 @@
 There are three ways to add new scheduling rules (predicates and priority
 functions) to Kubernetes: (1) by adding these rules to the scheduler and
 recompiling (described here:
-https://github.com/kubernetes/kubernetes/blob/master/docs/devel/scheduler.md),
+https://github.com/kubernetes/community/blob/master/contributors/devel/scheduler.md),
 (2) implementing your own scheduler process that runs instead of, or alongside
 of, the standard Kubernetes scheduler, (3) implementing a "scheduler extender"
 process that the standard Kubernetes scheduler calls out to as a final pass when