Fixes: https://github.com/spring-projects/spring-integration/issues/3822 * Apply spring-framework code style on modified class * Remove unwanted formatting * Take pull request comments into account * Code and JavaDocs clean up * Improve `Mqttv5BackToBackAutomaticReconnectTests` removing non-related code * Improve `mqtt.adoc` for this new manual reconnection feature **Cherry-pick to `5.5.x`**