[Form] Remove some unnecessary versionadded directives

Author: javiereguiluz

reference/forms/types/form.rst

@@ -86,10 +86,6 @@ the underlying object that will be used to populate the form field.
 
 More details are available in the section on :doc:`/form/data_mappers`.
 
-.. versionadded:: 5.2
-
-    Form mapping callbacks were added in Symfony 5.2.
-
 .. include:: /reference/forms/types/options/help.rst.inc
 
 .. include:: /reference/forms/types/options/help_attr.rst.inc
@@ -136,10 +132,6 @@ back to the underlying object.
 
 More details are available in the section on :doc:`/form/data_mappers`.
 
-.. versionadded:: 5.2
-
-    Form mapping callbacks were added in Symfony 5.2.
-
 .. include:: /reference/forms/types/options/trim.rst.inc
 
 .. include:: /reference/forms/types/options/validation_groups.rst.inc