Rollup merge of #47874 - jcowgill:mips-from_raw_os_error, r=dtolnay

std: use more portable error number in from_raw_os_error docs

On MIPS, error number 98 is not `EADDRINUSE` (it is `EPROTOTYPE`). To fix the resulting test failure this causes, use a more portable error number in the example documentation. `EINVAL` shold be more reliable because it was defined in the original Unix as 22 so hopefully most derivatives have defined it the same way.