net: remove some BUG entries

A few methods that were not implemented on Windows are implemented
in CL 668195.

Change-Id: I35423792a5af00f29fcd24e56a6dfcf013669371
Reviewed-on: https://go-review.googlesource.com/c/go/+/680180
Reviewed-by: Quim Muntal <quimmuntal@gmail.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Carlos Amedee <carlos@golang.org>

Author: cherrymui

src/net/iprawsock.go

@@ -24,9 +24,6 @@ import (
 // BUG(mikio): On JS and Plan 9, methods and functions related
 // to IPConn are not implemented.
 
-// BUG(mikio): On Windows, the File method of IPConn is not
-// implemented.
-
 // IPAddr represents the address of an IP end point.
 type IPAddr struct {
 	IP   IP

src/net/tcpsock.go

@@ -14,7 +14,7 @@ import (
 	"time"
 )
 
-// BUG(mikio): On JS and Windows, the File method of TCPConn and
+// BUG(mikio): On JS, the File method of TCPConn and
 // TCPListener is not implemented.
 
 // TCPAddr represents the address of a TCP end point.

src/net/udpsock.go

@@ -14,9 +14,6 @@ import (
 // BUG(mikio): On Plan 9, the ReadMsgUDP and
 // WriteMsgUDP methods of UDPConn are not implemented.
 
-// BUG(mikio): On Windows, the File method of UDPConn is not
-// implemented.
-
 // BUG(mikio): On JS, methods and functions related to UDPConn are not
 // implemented.