docs(elbv2): clarify target group documentation (#24938)

The Target Group documentation improperly described the `port` property
as where the _listener_ listened for traffic; however, this property is
for the _target group_ and has no bearing on any created listeners.
Additionally, `protocol` is not just optional for Lambda functions, it
is entirely ignored.

This updates the wording to be slightly closer to the documentation on
the `AWS::ElasticLoadBalancingV2::TargetGroup` resource documentation
from CloudFormation.

----

*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

Author: laurelmay

packages/aws-cdk-lib/aws-elasticloadbalancingv2/lib/alb/application-target-group.ts

@@ -18,9 +18,11 @@ import { determineProtocolAndPort, parseLoadBalancerFullName, parseTargetGroupFu
  */
 export interface ApplicationTargetGroupProps extends BaseTargetGroupProps {
   /**
-   * The protocol to use
+   * The protocol used for communication with the target.
    *
-   * @default - Determined from port if known, optional for Lambda targets.
+   * This is not applicable for Lambda targets.
+   *
+   * @default - Determined from port if known
    */
   readonly protocol?: ApplicationProtocol;
 
@@ -32,9 +34,11 @@ export interface ApplicationTargetGroupProps extends BaseTargetGroupProps {
   readonly protocolVersion?: ApplicationProtocolVersion;
 
   /**
-   * The port on which the listener listens for requests.
+   * The port on which the target receives traffic.
+   *
+   * This is not applicable for Lambda targets.
    *
-   * @default - Determined from protocol if known, optional for Lambda targets.
+   * @default - Determined from protocol if known
    */
   readonly port?: number;
 

packages/aws-cdk-lib/aws-elasticloadbalancingv2/lib/nlb/network-target-group.ts

@@ -15,7 +15,7 @@ import { parseLoadBalancerFullName, parseTargetGroupFullName, validateNetworkPro
  */
 export interface NetworkTargetGroupProps extends BaseTargetGroupProps {
   /**
-   * The port on which the listener listens for requests.
+   * The port on which the target receives traffic.
    */
   readonly port: number;