JIRA: https://jira.spring.io/browse/INT-3876
INT-3876 track groups ids in AbstractCorrelatingMessageHandler and docs
INT-3876 Fix merge conflict and add missing link in doc
INT-3876 Move groupId check in message group processor and rework on docs
INT-3876 Remove extra space from the doc
INT-3876 Fix checkstyle refer instance variable groupid correctly
INT-3876 Update aggregator doc with more details
* Polishing `aggregator.adoc`
* Rework `AbstractCorrelatingMessageHandlerTests.testDontReapMessageOfOtherHandler`
do not use redundant options
96aa7280a0