[DOC beta] Add note about using `{{#with as}}`
[DOC beta] Docs for over-riding default behavior in `setupController`
Merge pull request #4446 from bradfol/setup-controller-doc

[DOC beta] Docs for over-riding default behavior in `setupController`
Merge pull request #4440 from bradfol/with-as-doc

[DOC beta] Add note about using `{{#with as}}`