Bug: Sequential macro provide forward_mut as forward

[uselessgoddess]

Because of this models like BatchNorm2D crashes while training.

dfdx/dfdx/src/nn/layers/batch_norm2d.rs

Line 92 in 370334f

assert!(!T::OWNS_TAPE);

dfdx/dfdx-derives/src/lib.rs

Lines 519 to 522 in 370334f

	fn try_forward(&self, x: Input) -> Result<Self::Output, Error> {
	#src
	Ok(x)
	}