added param comment

Author: colerogers

src/v2/providers/alerts/alerts.ts

@@ -50,6 +50,7 @@ export interface FirebaseAlertOptions extends options.EventHandlerOptions {
 /**
  * Declares a function that can handle Firebase Alerts from CloudEvents
  * @param alertTypeOrOpts the alert type or Firebase Alert function configuration
+ * @param handler a function that can handle the Firebase Alert inside a CloudEvent
  */
 export function onAlertPublished<T extends { ['@type']: string } = any>(
   alertTypeOrOpts: AlertType | FirebaseAlertOptions,