io::ErrorKind for ENOSPC (no space left)

I recently realized there is no variant of io::ErrorKind equivalent to ENOSPC (no space left on device). Is there a reason why it doesn't exist, or would it be a candidate to be added some day? After all, it's a common kind of error which can occur on every OS, I assume.

There's a PR in progress to add this and other errors to ErrorKind.