libstd: Document the following modules:

* native::io
* std::char
* std::fmt
* std::fmt::parse
* std::io
* std::io::extensions
* std::io::net::ip
* std::io::net::udp
* std::io::net::unix
* std::io::pipe
* std::num
* std::num::f32
* std::num::f64
* std::num::strconv
* std::os

src/libstd/io/net/unix.rs

@@ -79,7 +79,9 @@ impl Writer for UnixStream {
     fn write(&mut self, buf: &[u8]) -> IoResult<()> { self.obj.write(buf) }
 }
 
+/// A value that can listen for incoming named pipe connection requests.
 pub struct UnixListener {
+    /// The internal, opaque runtime Unix listener.
     priv obj: ~RtioUnixListener,
 }
 
@@ -119,7 +121,9 @@ impl Listener<UnixStream, UnixAcceptor> for UnixListener {
     }
 }
 
+/// A value that can accept named pipe connections, returned from `listen()`.
 pub struct UnixAcceptor {
+    /// The internal, opaque runtime Unix acceptor.
     priv obj: ~RtioUnixAcceptor,
 }