Harmonize Discover the HTTP Port at Runtime How-To

See gh-22898

Author: johncfranco

spring-boot-project/spring-boot-docs/src/main/asciidoc/howto.adoc

@@ -498,7 +498,7 @@ To scan for a free port (using OS natives to prevent clashes) use `server.port=0
 [[howto-discover-the-http-port-at-runtime]]
 === Discover the HTTP Port at Runtime
 You can access the port the server is running on from log output or from the `ServletWebServerApplicationContext` through its `WebServer`.
-The best way to get that and be sure that it has been initialized is to add a `@Bean` of type `ApplicationListener<ServletWebServerInitializedEvent>` and pull the container out of the event when it is published.
+The best way to get that and be sure that it has been initialized is to add a `@Bean` of type `ApplicationListener<ServletWebServerInitializedEvent>`  (or `ApplicationListener<ReactiveWebServerInitializedEvent>` for reactive servers) and pull the container out of the event when it is published.
 
 Tests that use `@SpringBootTest(webEnvironment=WebEnvironment.RANDOM_PORT)` can also inject the actual port into a field by using the `@LocalServerPort` annotation, as shown in the following example: