Document unofficial parameter in phpdoc

[greg0ire]

This is a follow-up for #9747 (comment)

Pros:

• The DebugClassLoader of Symfony can emit a deprecation about that
• The phpdoc no longer needs to be repeated in implementing classes

Cons:

• PHP_CodeSniffer is unhappy about this.
• PHPStan is unhappy about this.
• Psalm does not take into account the inherited phpdoc.

[greg0ire]

@stof this does not look too great: we have to add ignore rules for 3 of our tools, to trigger a deprecation for a tool that isn't necessarily used by our users.

[SenseException]

It seems like @param class-string $className The fully-qualified class name. had to be added to the classes instead of the interface. Maybe using the psalm- or phpstan annotations than the phpdoc one.

[greg0ire]

@SenseException the goal of this is to trigger a deprecation at autoload time for implementing classes outside doctrine/orm, so the interface phpdoc has to be modified. That being said, given the cons I listed, I'm not convinced this is a great idea, so let's just close this.