As just discussed in Slack/Discord it is not clear, that these two method calls don't lead to the same result:

// works as expected
$entity = $this->patchEntity($entity, $data, ['associated' => ['First.Second', 'First.Third', 'First.Fourth']]);

// won't patch Second, Third and Four
$entity = $this->patchEntity($entity, $data, ['associated' => ['First' => ['Second', 'Third', 'Fourth']]]); 

One would image/expect that this array structure behaves the same as a e.g. contain() array structure but it doesn't.

This PR at least adjusts the docs generated for api.cakephp.org including 2 separate tests to make sure this actually works and to link to if someone has questions about it.

We should make this clearer in the Book as well