Make scopes API docs visible
Make scopes API docs visible

closes PLAT-3471

Test Plan:
- verify docs:api rake task is successful
- verify documentation for scopes api controller
  is visible.
- verify documentation for scopes api controller
  is clearly marked as "beta."

Change-Id: I131c96de50cada9c89a25547c286cedfb0ffacc7
Reviewed-on: https://gerrit.instructure.com/153357
Tested-by: Jenkins
Reviewed-by: August Thornton <9adc7a1161ddf32ff608de792a7e50179545f026@instructure.com>
QA-Review: August Thornton <9adc7a1161ddf32ff608de792a7e50179545f026@instructure.com>
Reviewed-by: Stewie aka Nicholas Stewart <bec99285d8f1953757afca2af84365b0776c1eb4@instructure.com>
Product-Review: Jesse Poulos <0a3f73d5b21621dbbacf36ae20620a7eb669a89e@instructure.com>

sfu/canvas-lms,sfu/canvas-lms,djbender/canvas-lms,instructure/canvas-lms,djbender/canvas-lms,sfu/canvas-lms,djbender/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,instructure/canvas-lms,instructure/canvas-lms,sfu/canvas-lms,djbender/canvas-lms,instructure/canvas-lms,instructure/canvas-lms,sfu/canvas-lms,instructure/canvas-lms,instructure/canvas-lms