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
@@ -256,6 +256,7 @@ class DenseFeatures(Layer[Mapping[str, TensorLike], tf.Tensor]):
     ) -> None: ...
 
 class MultiHeadAttention(Layer[Any, tf.Tensor]):
+    @override
     def __init__(
         self,
         num_heads: int,