K8s: Update Node Pool documentation (#1517)

* K8s: Update Node Pool documentation 

Addressing #1516

Adding explicit documentation that minimum node pool size can't not be zero if autoscale is true.

* Update kubernetes.go

* update node pool doc

---------

Co-authored-by: Andrew Starr-Bochicchio <andrewsomething@users.noreply.github.com>

commands/kubernetes.go

@@ -301,8 +301,8 @@ Format: `+"`"+`"name=your-name;size=size_slug;count=5;tag=tag1;tag=tag2;label=ke
 - `+"`"+`tag`+"`"+`: A comma-separated list of tags to apply to nodes in the pool
 - `+"`"+`label`+"`"+`: A label in `+"`"+`key=value`+"`"+` notation. Repeat to add multiple labels at once.
 - `+"`"+`taint`+"`"+`: Taint in `+"`"+`key=value:effect`+"`"+` notation. Repeat to add multiple taints at once.
-- `+"`"+`auto-scale`+"`"+`: Enables cluster auto-scaling on the node pool (boolean)
-- `+"`"+`min-nodes`+"`"+`: The minimum number of nodes that the cluster can be auto-scaled to.
+- `+"`"+`auto-scale`+"`"+`: Enables cluster auto-scaling on the node pool (boolean).
+- `+"`"+`min-nodes`+"`"+`: The minimum number of nodes that the cluster can be auto-scaled to. The value will be 0 if auto_scale is set to false. Scale-to-zero is not supported.
 - `+"`"+`max-nodes`+"`"+`: The maximum number of nodes that can be auto-scaled to.`)
 
 	AddBoolFlag(cmdKubeClusterCreate, doctl.ArgClusterUpdateKubeconfig, "", true,
@@ -490,7 +490,7 @@ Creates a new node pool for the specified cluster. The command requires values f
 	AddBoolFlag(cmdKubeNodePoolCreate, doctl.ArgNodePoolAutoScale, "", false,
 		"Enables auto-scaling on the node pool")
 	AddIntFlag(cmdKubeNodePoolCreate, doctl.ArgNodePoolMinNodes, "", 0,
-		"The minimum number of nodes in the node pool when autoscaling is enabled")
+		"The minimum number of nodes in the node pool when autoscaling (auto_scale) is enabled. If auto_scale is set to false, the default value will be 0. Scale-to-zero is not supported.")
 	AddIntFlag(cmdKubeNodePoolCreate, doctl.ArgNodePoolMaxNodes, "", 0,
 		"The maximum number of nodes in the node pool when autoscaling is enabled")
 	cmdKubeNodePoolCreate.Example = `The following example creates a node pool named ` + "`" + `example-pool` + "`" + ` in a cluster named ` + "`" + `example-cluster` + "`" + `: doctl kubernetes cluster node-pool create example-cluster --name example-pool --size s-1vcpu-2gb --count 3 --taint "key1=value1:NoSchedule" --taint "key2:NoExecute"`