netlink: document that Conn.Close bug #162 is fixed

Signed-off-by: Matt Layher <mdlayher@gmail.com>

conn.go

@@ -97,13 +97,7 @@ func (c *Conn) debug(fn func(d *debugger)) {
 	fn(c.d)
 }
 
-// Close closes the connection.
-//
-// Due to a bug https://github.com/mdlayher/netlink/issues/162, Close currently
-// cannot unblock concurrent calls to Send or Receive. As a stop-gap measure,
-// call SetDeadline with a time in the past such as time.Unix(1, 0) in a
-// different goroutine to unblock a long-running Receive loop. The intent is to
-// fix this issue in v1.2.0.
+// Close closes the connection and unblocks any pending read operations.
 func (c *Conn) Close() error {
 	// Close does not acquire a lock because it must be able to interrupt any
 	// blocked system calls, such as when Receive is waiting on a multicast