doc: Add link of ECMAScript 2015
This is part of Nodefest's Code and Learn nodejs/code-and-learn#72 I add link of ECMAScript 2015.
Checklist
-
documentation is changed or added -
commit message follows commit guidelines
Do not update/delete: Banner broadcast message test data
Do not update/delete: Notification broadcast message test data
This is part of Nodefest's Code and Learn nodejs/code-and-learn#72 I add link of ECMAScript 2015.