hg: jdk9/sandbox/jdk: 8178725: provide way to link to external documentation

[chris.hegarty at oracle.com]

Changeset: fd5c621ad3b1
Author:    ksrini
Date:      2017-04-25 07:52 -0700
URL:       http://hg.openjdk.java.net/jdk9/sandbox/jdk/rev/fd5c621ad3b1

8178725: provide way to link to external documentation
Reviewed-by: erikj, ihse, jjg

+ make/src/classes/build/tools/taglet/ExtLink.java