docs: Simplify values comment

Signed-off-by: younsl <cysl@kakao.com>

Author: younsl

charts/docker-mailserver/values.yaml

@@ -302,8 +302,7 @@ service:
   # externalTrafficPolicy: "Cluster"
   ## Traffic distribution preference for Services. One of:
   ## - PreferClose (routes traffic to endpoints that are topologically proximate)
-  ## This field requires Kubernetes 1.31+ and is only available when the feature gate is enabled.
-  ## See: https://kubernetes.io/docs/concepts/services-networking/service/#traffic-distribution
+  ## Traffic distribution for multi-zone topology (Kubernetes 1.31+)
   trafficDistribution: ""
   ## If there is a port associated with a given service, expose it here.
   # port: