rubocop: bump rubocop-rails

also fix a lint error that snuck in before it was enforced, and clean up
the api_scope_mapper_template.erb so that the generated file lints
cleanly

Change-Id: I2491fc9b9753217a6ebaf79fc2404151f9d2ecdf
Reviewed-on: https://gerrit.instructure.com/c/canvas-lms/+/276968
Tested-by: Service Cloud Jenkins <svc.cloudjenkins@instructure.com>
Reviewed-by: Jacob Burroughs <jburroughs@instructure.com>
QA-Review: Cody Cutrer <cody@instructure.com>
Product-Review: Cody Cutrer <cody@instructure.com>

Gemfile.d/rubocop.rb

@@ -34,7 +34,7 @@ group :test do
     gem 'unicode-display_width', '2.1.0', require: false
   gem 'rubocop-canvas', require: false, path: "gems/rubocop-canvas"
     gem 'rainbow', '3.0.0', require: false
-  gem 'rubocop-rails', '2.12.3', require: false
+  gem 'rubocop-rails', '2.12.4', require: false
   gem 'rubocop-rake', '0.6.0', require: false
   gem 'rubocop-rspec', '2.5.0', require: false
   gem 'rubocop-performance', '1.11.5', require: false

app/models/quizzes/preloader.rb

@@ -36,7 +36,7 @@ module Quizzes
     # By including this module in the root quizzes module, we'll fire off explicit
     # loading for each of the constants we care about as soon as we start referencing the Quizzes module
     # anywhere, which should be early enough to prevent FS read order confusion.
-    def self.included(base)
+    def self.included(_base)
       Preloader.preload_quiz_questions
     end
   end

doc/api/fulldoc/html/api_scopes/scope_mapper_template.erb

@@ -27,7 +27,6 @@
 ###########################################################################################
 
 class ApiScopeMapper
-
   SCOPE_MAP = {
   <% mapping.each_with_index do |(controller, children), i| -%>
   <%="#{controller}: {" %>
@@ -39,9 +38,9 @@ class ApiScopeMapper
 }.freeze
 
   RESOURCE_NAMES = {
-    oauth2: -> {I18n.t('OAuth 2')},
-    peer_services: -> {I18n.t('Peer Services')},
-    <%=resource_lookup.map { |k, v| "#{k}: -> {I18n.t('#{v}')}"}.join(",\n    " ) %>
+    oauth2: -> { I18n.t('OAuth 2') },
+    peer_services: -> { I18n.t('Peer Services') },
+    <%=resource_lookup.map { |k, v| "#{k}: -> { I18n.t('#{v}') }"}.join(",\n    " ) %>
   }.freeze
 
   def self.lookup_resource(controller, action)
@@ -52,5 +51,4 @@ class ApiScopeMapper
   def self.name_for_resource(resource)
     RESOURCE_NAMES[resource]&.call
   end
-
 end