doc: state possible total_egress_bandwidth_tier values (#14173) (#10124)

[upstream:ce403786b12b9f9572458270bf907e550b882d26]

Signed-off-by: Modular Magician <magic-modules@google.com>

Author: modular-magician

google-beta/services/container/resource_container_node_pool.go

@@ -482,7 +482,7 @@ var schemaNodePool = map[string]*schema.Schema{
 							"total_egress_bandwidth_tier": {
 								Type:        schema.TypeString,
 								Required:    true,
-								Description: `Specifies the total network bandwidth tier for the NodePool.`,
+								Description: `Specifies the total network bandwidth tier for the NodePool. [Valid values](https://cloud.google.com/kubernetes-engine/docs/reference/rest/v1/projects.locations.clusters.nodePools#NodePool.Tier) include: "TIER_1" and "TIER_UNSPECIFIED".`,
 							},
 						},
 					},

website/docs/r/container_node_pool.html.markdown

@@ -254,7 +254,8 @@ cluster.
 
 <a name="network_performance_config"></a>The `network_performance_config` block supports:
 
-* `total_egress_bandwidth_tier` (Required) - Specifies the total network bandwidth tier for the NodePool.
+* `total_egress_bandwidth_tier` (Required) - Specifies the total network bandwidth tier for the NodePool. [Valid values](https://cloud.google.com/kubernetes-engine/docs/reference/rest/v1/projects.locations.clusters.nodePools#NodePool.Tier) include: "TIER_1" and "TIER_UNSPECIFIED".
+* ```
 
 <a name="pod_cidr_overprovision_config"></a>The `pod_cidr_overprovision_config` block supports: