Add instructions for enabling MSWORD Mendeley Add-In

[chapb]

When Mendeley's word plug in is installed, it is not shown on the ribbon, and we can't enable it.

However, we can expose the features normally on the ribbon by adding the macros directly to the ribbon.

1. Customize Ribbon
2. From Macros to New Group
3. Add insert.citation, add insert.bibliography, add select.citation.style