NIO: expose `LINGER` as a public type on Windows (#1675)
NIO: expose `LINGER` as a public type on Windows (#1675)

The Windows `LINGER` type is meant to be exposed as it is a low-level
system detail for `SocketChannelOptions`.  See #1673 for relevant
discussion.

Co-authored-by: Cory Benfield <e2b4f0650e369574e9b0029c3b3893634b6d4097@apple.com>
apple/swift-nio,apple/swift-nio,apple/swift-nio,apple/swift-nio,apple/swift-nio