AWS: Fixed link to the detailed explanation

kubernetes-retired/contrib#1552 (comment) seems to explain the reasoning behind multiple ASGs much better then the previous link target.

cluster-autoscaler/cloudprovider/aws/README.md

@@ -215,7 +215,7 @@ spec:
 
 Common Notes and Gotchas:
 - The `/etc/ssl/certs/ca-certificates.crt` should exist by default on your ec2 instance.
-- Cluster autoscaler is not zone aware (for now), so if you wish to span multiple availability zones in your autoscaling groups beware that cluster autoscaler will not evenly distribute them. For more information, see https://github.com/kubernetes/contrib/pull/1552#discussion_r75533090.
+- Cluster autoscaler is not zone aware (for now), so if you wish to span multiple availability zones in your autoscaling groups beware that cluster autoscaler will not evenly distribute them. For more information, see https://github.com/kubernetes/contrib/pull/1552#r75532949.
 - By default, cluster autoscaler will not terminate nodes running pods in the kube-system namespace. You can override this default behaviour by passing in the `--skip-nodes-with-system-pods=false` flag.
 - By default, cluster autoscaler will wait 10 minutes between scale down operations, you can adjust this using the `--scale-down-delay` flag. E.g. `--scale-down-delay=5m` to decrease the scale down delay to 5 minutes.
 - If you're running multiple ASGs, the `--expander` flag supports three options: `random`, `most-pods` and `least-waste`. `random` will expand a random ASG on scale up. `most-pods` will scale up the ASG that will scheduable the most amount of pods. `least-waste` will expand the ASG that will waste the least amount of CPU/MEM resources. In the event of a tie, cluster autoscaler will fall back to `random`.