hg: amber/amber: document exceptions

[paul.sandoz at oracle.com]

Changeset: 31dc3ce9ed87
Author:    psandoz
Date:      2017-10-20 16:03 -0500
URL:       http://hg.openjdk.java.net/amber/amber/rev/31dc3ce9ed87

document exceptions

! src/java.base/share/classes/java/lang/invoke/Bootstraps.java