hi @kunicmarko20, thanks for review.
IMO one callback is always a function, even if it has this format[$object, 'methodName'].
For me callback method indicates rather that we expect a callback in the format [$object, 'methodName'] and not in trim for exemple.

 .. code-block:: php-annotations
 
     /**
      * @ORM\Entity()
      * @ORM\HasLifecycleCallbacks()
      */
     class Product
     {
         // ...
     }
 
 Now, you can tell Doctrine to execute a method on any of the available lifecycle
 events. For example, suppose you want to set a ``createdAt`` date column to
 the current date, only when the entity is first persisted (i.e. inserted):
 
 .. configuration-block::
 
     .. code-block:: php-annotations
 
         // src/Entity/Product.php
 
         /**
          * @ORM\PrePersist
          */
         public function setCreatedAtValue()
         {
             $this->createdAt = new \DateTime();
         }
 
     .. code-block:: yaml
 
         # config/doctrine/Product.orm.yml
         App\Entity\Product:
             type: entity
             # ...
             lifecycleCallbacks:
                 prePersist: [setCreatedAtValue]

This is the example I was talking about, so setCreatedAtValue is the callback here and it is clearly a method and not a function?

So you would say if it was like prePersist: [$product, setCreatedAtValue] then it would be a method and not a function?

I disagree with this but I am not a decider, will leave it to the symfony docs team.

btw, thank you for the contribution! 😄

I rebased the branch and changed thre PR base to 3.4.

@ottaviano thanks for this contribution! Sadly this PR contains too many changes: some are obvious, others have been challenged by reviewers and others don't look right (like the form help related changes, which were introduced in 4.x, not 3.4). So, I've created #11109 with the obvious fixes you did here and we can create in the future other PRs to change other things. Thank you!