Improve IO::Socket::INET.accept() documentation.

Specify that a new socket instance is returned by such method.
Close issue #1929.

Description as of rakudo source 2018.01.

Author: fluca1978

doc/Type/IO/Socket/INET.pod6

@@ -89,6 +89,8 @@ Returns a lazy list of lines read from the socket.
 
     method accept()
 
-In listen/server mode, waits for a new incoming connection, and returns it.
+In listen/server mode, waits for a new incoming connection.
+Once a new connection is established, the C<IO::Socket::INET>
+instance for consuming the connection is returned.
 
 =end pod