Move some layers to keras.layers.preprocessing

stubs/tensorflow/tensorflow/keras/layers/__init__.pyi

@@ -1,7 +1,7 @@
 from _typeshed import Incomplete
 from collections.abc import Callable, Iterable, Mapping, Sequence
 from typing import Any, Generic, Literal, TypeVar, overload
-from typing_extensions import Self, TypeAlias
+from typing_extensions import Self, TypeAlias, override
 
 import tensorflow as tf
 from tensorflow import Tensor, Variable, VariableAggregation, VariableSynchronization, _TensorCompatible
@@ -273,7 +273,7 @@ class MultiHeadAttention(Layer[Any, tf.Tensor]):
         kernel_constraint: _Constraint | None = None,
         bias_constraint: _Constraint | None = None,
         trainable: bool = True,
-        dtype: _LayerDtype = None,
+        dtype: _LayerDtype | None = None,
         dynamic: bool = False,
         name: str | None = None,
     ) -> None: ...