erroneous assert encoded >= 0xf001

This one: https://github.com/bytecodealliance/rustix/blob/cd9520157e08e4e70b2fc9c2e9aacb18c8d23439/src/backend/linux_raw/io/errno.rs#L91

Is causing issues here: https://github.com/Smithay/smithay/issues/1725 . I think the issue is that the assert fails when errno is `0`, because wrapping_neg puts it back to `0`. This is also what is shown in my corefile of the crash