Clarify container-concurrency-target-default works for hpa as well. (k…

…native#3273)

config/config-autoscaler.yaml

@@ -47,8 +47,11 @@ data:
     container-concurrency-target-percentage: "1.0"
 
     # The container concurrency target default is what the Autoscaler will
-    # try to maintain when the Revision specifies unlimited concurrency. A
-    # value of 100 is chosen because it's enough to allow vertical pod
+    # try to maintain when the Revision specifies unlimited concurrency.
+    # Even when specifying unlimited concurrency, the autoscaler will
+    # horizontally scale the application based on this target concurrency.
+    #
+    # A value of 100 is chosen because it's enough to allow vertical pod
     # autoscaling to tune resource requests. E.g. maintaining 1 concurrent
     # "hello world" request doesn't consume enough resources to allow VPA
     # to achieve efficient resource usage (VPA CPU minimum is 300m).