add doc on customizing moment.js date formats

[tkimnguyen]

Where to add this customization documentation? https://5.docs.plone.org/adapt-and-extend/index.html ?

The new moment.js formats dates so they show up as "7 days ago", "3 days ago", etc.

To make a configuration change so the full dates are shown in the Contents view, e.g. https://mysite.com/folder_contents, go to the Resource Registry control panel, click "Pattern Options" tab, add a pattern called "structure" and give it the value

{ "momentFormat": "MMMM D, YYYY" }

For more information about moment.js formats, see http://momentjs.com