Source code documentation updates (#9)

This change adds documentation to quite a few existing public types that
didn't have a blurb before.

Additionally, this fixes a couple things that I think either didn't make
sense when going to document them:
- Rename ConnectionStream to VsockConnectionStream. This type only
functions for vsock connections.
- Deletes NsLock+Closure. This was not used anywhere.
- Rename ContainerizationOCI/Config.swift to ImageConfig.swift.

Signed-off-by: Danny Canter <danny_canter@apple.com>

Sources/ContainerizationOS/Socket/Socket.swift

@@ -44,6 +44,7 @@ let sysConnect = connect
 let sysIoctl: @convention(c) (CInt, CUnsignedLong, UnsafeMutableRawPointer) -> CInt = ioctl
 #endif
 
+/// Thread-safe socket wrapper.
 public final class Socket: Sendable {
     public enum TimeoutOption {
         case send

Sources/ContainerizationOS/Socket/SocketType.swift

@@ -24,6 +24,7 @@ import Darwin
 #error("SocketType not supported on this platform.")
 #endif
 
+/// Protocol used to describe the family of socket to be created with `Socket`.
 public protocol SocketType: Sendable, CustomStringConvertible {
     var domain: Int32 { get }
     var type: Int32 { get }

Sources/ContainerizationOS/Socket/UnixType.swift

@@ -27,6 +27,7 @@ let _SOCK_STREAM = SOCK_STREAM
 #error("UnixType not supported on this platform.")
 #endif
 
+/// Unix domain socket variant of `SocketType`.
 public struct UnixType: SocketType, Sendable, CustomStringConvertible {
     public var domain: Int32 { AF_UNIX }
     public var type: Int32 { _SOCK_STREAM }

Sources/ContainerizationOS/Socket/VsockType.swift

@@ -26,6 +26,7 @@ import Darwin
 #error("VsockType not supported on this platform.")
 #endif
 
+/// Vsock variant of `SocketType`.
 public struct VsockType: SocketType, Sendable {
     public var domain: Int32 { AF_VSOCK }
     public var type: Int32 { _SOCK_STREAM }