hg: jdk9/sandbox/langtools: Merge from default

[erik.joelsson at oracle.com]

Changeset: f49a13d9f1ba
Author:    erikj
Date:      2016-12-27 11:54 +0100
URL:       http://hg.openjdk.java.net/jdk9/sandbox/langtools/rev/f49a13d9f1ba

Merge from default

- src/jdk.jshell/share/classes/jdk/jshell/overview.html