RFR: 8036608: Key.getAlgorithm link to standard algorithm names needs to be updated

[Sean Mullan]

Please review this javadoc only change to be more specific about the 
standard algorithm names that Key.getAlgorithm may return. The fix lists 
the specific sections of the Standard Algorithm Names specification that 
are relevant.

webrev: http://cr.openjdk.java.net/~mullan/webrevs/8036608/webrev.00/
bug: https://bugs.openjdk.java.net/browse/JDK-8036608
Thanks,
Sean