minor #21431 [PropertyInfo] Improved the explanation of the with_constructor_extractor option (javiereguiluz)

This PR was squashed before being merged into the 7.3 branch.

Discussion
----------

[PropertyInfo] Improved the explanation of the with_constructor_extractor option

In #21060 we're removing this config option, so I think we should better explain its purpose.

Commits
-------

001263e [PropertyInfo] Improved the explanation of the with_constructor_extractor option

Author: javiereguiluz

reference/configuration/framework.rst

@@ -2578,6 +2578,8 @@ using the :ref:`ConstructorExtractor <components-property-information-constructo
 .. versionadded:: 7.3
 
     The ``with_constructor_extractor`` option was introduced in Symfony 7.3.
+    It's required to set a value for it because its default value will change
+    from ``false`` to ``true`` in Symfony 8.0.
 
 rate_limiter
 ~~~~~~~~~~~~