fastify/fastify-websocket

AI Summary: The task is to modify the `@fastify/websocket` plugin's `injectWS` function to automatically register a 'ping' event listener that responds with a 'pong' message. This addresses an issue where the default behavior omits this crucial part of the WebSocket handshake, leading to dropped pings and potential test failures. The fix involves adding a single line of code within the existing `injectWS` function.