RFR: 8235141: Specify the required standard socket options for the socket types in the java.net package

[Daniel Fuchs]

Hi,

Please find below a doc-only fix that specifies, for each
socket type in the java.net package, the minimal set of option
that that type supports.

The doc changes have been largely imported from corresponding
types in java.nio.channels.


8235141: Specify the required standard socket options for the
          socket types in the java.net package
https://bugs.openjdk.java.net/browse/JDK-8235141

webrev:
http://cr.openjdk.java.net/~dfuchs/webrev_8235141/webrev.00/

CSR:
https://bugs.openjdk.java.net/browse/JDK-8235185

best regards,

-- daniel