docs: Improve karpenter discovery tags example (#3097)

* docs: Improve karpenter discovery tags example

* chore: Re-add general tags declaration

---------

Co-authored-by: Bryant Biggs <bryantbiggs@gmail.com>

examples/karpenter/main.tf

@@ -101,12 +101,20 @@ module "eks" {
     }
   }
 
-  tags = merge(local.tags, {
+  # cluster_tags = merge(local.tags, {
+  #   NOTE - only use this option if you are using "attach_cluster_primary_security_group"
+  #   and you know what you're doing. In this case, you can remove the "node_security_group_tags" below.
+  #  "karpenter.sh/discovery" = local.name
+  # })
+
+  node_security_group_tags = merge(local.tags, {
     # NOTE - if creating multiple security groups with this module, only tag the
     # security group that Karpenter should utilize with the following tag
     # (i.e. - at most, only one security group should have this tag in your account)
     "karpenter.sh/discovery" = local.name
   })
+
+  tags = local.tags
 }
 
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