Fix the Doc of the combination relation in func `keras.layers.Normalization()`

[ILCSFNO]

Doc Issue

The doc of keras.layers.Normalization() shows its description as below:

keras/keras/src/layers/preprocessing/normalization.py

Lines 42 to 49 in 3fac66f

	mean: The mean value(s) to use during normalization. The passed value(s)
	will be broadcast to the shape of the kept axes above;
	if the value(s) cannot be broadcast, an error will be raised when
	this layer's `build()` method is called.
	variance: The variance value(s) to use during normalization. The passed
	value(s) will be broadcast to the shape of the kept axes above;
	if the value(s) cannot be broadcast, an error will be raised when
	this layer's `build()` method is called.

For the repro below, I accept that it should error, but need to be noted in the docstring:

Repro

import keras
normalizer = keras.layers.Normalization(axis=1, mean=0.5)
print(normalizer)

Output

ValueError: When setting values directly, both `mean` and `variance` must be set. Received: mean=0.5 and variance=None

The error related is defined here:

keras/keras/src/layers/preprocessing/normalization.py

Lines 119 to 124 in 3fac66f

	# Set `mean` and `variance` if passed.
	if (mean is not None) != (variance is not None):
	raise ValueError(
	"When setting values directly, both `mean` and `variance` "
	f"must be set. Received: mean={mean} and variance={variance}"
	)

Thanks a lot!

[ILCSFNO]

PR opened here, thanks a lot!

• Fix the Doc of the combination relation in func keras.layers.Normalization() #21716