[Docs] Make clear that calling remove() detaches the object (doctrine#8081)

I changed a relationship from eager to lazy loading which broker the behaviour of my application in regards to object removal. It was not clear for me that removing an object detaches it and subsequent calls like contains() in a OneToMany relationship with the object scheduled for removal will return false afterwards.

Author: arneee

docs/en/reference/working-with-objects.rst

@@ -330,6 +330,13 @@ in multiple ways with very different performance impacts.
    because Doctrine will fetch and remove all associated entities
    explicitly nevertheless.
 
+.. note::
+
+    Calling ``remove`` on an entity will remove the object from the identiy
+    map and therefore detach it. Querying the same entity again, for example 
+    via a lazy loaded relation, will return a new object. 
+
+
 Detaching entities
 ------------------