Simd::load implementation does not match documentation

[RalfJung]

The load function is documented as follows:

portable-simd/crates/core_simd/src/vector.rs

Lines 191 to 197 in 8d9bcda

	/// Load a vector from an array of `T`.
	///
	/// This function is necessary since `repr(simd)` has padding for non-power-of-2 vectors (at the time of writing).
	/// With padding, `read_unaligned` will read past the end of an array of N elements.
	///
	/// # Safety
	/// Reading `ptr` must be safe, as if by `<*const [T; N]>::read_unaligned`.

In particular, the last part says that there are no alignment restrictions on the pointer. However, the implementation performs a copy_nonoverlapping at type [T; N], which means that ptr actually must be T-aligned. This is unsound under the stated precondition for this function. (There don't seem to be tests actually using this with unaligned pointers, so Miri can't catch this.)

It is unclear to me what the intended behavior is, though I would have expected that alignment is indeed required -- i.e., I would guess the docs are wrong and the code is right.