[Serializer] Add PRESERVE_CONTEXT_TIMEZONE_KEY to DateTimeNormalizer

- Updated docs to updated const

Author: frankdekker

serializer.rst

@@ -1375,8 +1375,8 @@ normalizers (in order of priority):
 
     To always create :phpclass:`DateTime` and :phpclass:`DateTimeImmutable`
     with the timezone specified in the context, set the
-    ``DateTimeNormalizer::PRESERVE_CONTEXT_TIMEZONE_KEY`` context option to
-    ``true``. This will preserve the timezone of the context and ignores any
+    ``DateTimeNormalizer::FORCE_TIMEZONE_KEY`` context option to
+    ``true``. This will force the timezone of the context and ignores any
     timezone from the input.
 
     To convert the objects to integers or floats, set the serializer
@@ -1387,9 +1387,9 @@ normalizers (in order of priority):
 
         The ``DateTimeNormalizer::CAST_KEY`` context option was introduced in Symfony 7.1.
 
-    .. versionadded:: 7.3
+    .. versionadded:: 7.4
 
-        The ``DateTimeNormalizer::PRESERVE_CONTEXT_TIMEZONE_KEY`` context option was introduced in Symfony 7.3.
+        The ``DateTimeNormalizer::FORCE_TIMEZONE_KEY`` context option was introduced in Symfony 7.3.
 
 :class:`Symfony\\Component\\Serializer\\Normalizer\\ConstraintViolationListNormalizer`
     This normalizer converts objects that implement