The REST API does not provide a mechanism to distinguish between endpoints representing models and those representing collections, so the Backbone client must make that distinction internally. Previously wp-api.js accounted for `/users/me`, but not for `/settings`. This patch updates the logic so that `/settings` is properly registered as a Backbone model.
When calling `wp.api.init`, additional endpoints can be specified to be models using the `modelEndpoints` argument.
Props @adamsilverstein.
Fixes#41056.
Built from https://develop.svn.wordpress.org/trunk@41112
git-svn-id: http://core.svn.wordpress.org/trunk@40952 1a063a9b-81f0-0310-95a4-ce76da25c4cd
6aaba32b36