Compiler Plugin Allows Passing an HTTP Listener with Configs to Listener Init

[ayeshLK]

Description:
When used with the check expression, WebSub/WebSubHub listener init function will allow passing additional configs with an HTTP listener variable.

The following scenarios should throw a compilation error, but it does not.

1. WebSub Listenet

import ballerina/websub;
import ballerina/http;

listener http:Listener httpListener = new(9090);
listener websub:Listener websubListener = check new(httpListener, timeout = 1000);

1. WebSubHub Listenet

import ballerina/websubhub;
import ballerina/http;

listener http:Listener httpListener = new(9090);
listener websubhub:Listener hubListener = check new(httpListener, timeout = 1000);