Subtracts an unsigned offset in bytes from a pointer using wrapping arithmetic.
`count` is in units of bytes.
This is purely a convenience for casting to a `u8` pointer and using
[`wrapping_sub`] on it. See that method for documentation.
For non-`Sized` pointees this operation changes only the data pointer, leaving
the metadata untouched.
# Original
[`<*T>::wrapping_byte_sub`][orig]
[orig]: https://doc.rust-lang.org/std/primitive.pointer.html#method.wrapping_byte_sub
[`wrapping_sub`]: Self::wrapping_sub