Make pending cops warning slightly more useful

CHANGELOG.md

@@ -28,6 +28,7 @@
 
 ### Changes
 
+* [#8413](https://github.com/rubocop-hq/rubocop/issues/8413): Pending cops warning now contains snippet that can be directly copied into `.rubocop.yml` as well as a notice about `NewCops: enable` config option. ([@colszowka][])
 * [#8376](https://github.com/rubocop-hq/rubocop/pull/8376): `Style/MethodMissingSuper` cop is removed in favor of new `Lint/MissingSuper` cop. ([@fatkodima][])
 * [#8350](https://github.com/rubocop-hq/rubocop/pull/8350): Set default max line length to 120 for `Style/MultilineMethodSignature`. ([@koic][])
 * [#8338](https://github.com/rubocop-hq/rubocop/pull/8338): **potentially breaking**. Config#for_department now returns only the config specified for that department; the 'Enabled' attribute is no longer calculated. ([@marcandre][])
@@ -4724,3 +4725,4 @@
 [@knejad]: https://github.com/knejad
 [@iamravitejag]: https://github.com/iamravitejag
 [@volfgox]: https://github.com/volfgox
+[@colszowka]: https://github.com/colszowka

lib/rubocop/config_loader.rb

@@ -140,22 +140,33 @@ def project_root
         @project_root ||= find_project_root
       end
 
+      PENDING_BANNER = <<~BANNER
+        The following cops were added to RuboCop, but are not configured. Please set Enabled to either `true` or `false` in your `.rubocop.yml` file.
+
+        Please also note that can also opt-in to new cops by default by adding this to your config:
+          AllCops:
+            NewCops: enable
+      BANNER
+
       def warn_on_pending_cops(pending_cops)
         return if pending_cops.empty?
 
-        warn Rainbow('The following cops were added to RuboCop, but are not ' \
-                     'configured. Please set Enabled to either `true` or ' \
-                     '`false` in your `.rubocop.yml` file:').yellow
+        warn Rainbow(PENDING_BANNER).yellow
 
         pending_cops.each do |cop|
-          version = cop.metadata['VersionAdded'] || 'N/A'
-
-          warn Rainbow(" - #{cop.name} (#{version})").yellow
+          warn_pending_cop cop
         end
 
         warn Rainbow('For more information: https://docs.rubocop.org/rubocop/versioning.html').yellow
       end
 
+      def warn_pending_cop(cop)
+        version = cop.metadata['VersionAdded'] || 'N/A'
+
+        warn Rainbow("#{cop.name}: # (new in #{version})").yellow
+        warn Rainbow('  Enabled: true').yellow
+      end
+
       # Merges the given configuration with the default one.
       def merge_with_default(config, config_file, unset_nil: true)
         resolver.merge_with_default(config, config_file, unset_nil: unset_nil)

spec/rubocop/cli/cli_options_spec.rb

@@ -272,7 +272,7 @@ class SomeCop < Cop
         end
 
         let(:pending_cop_warning) { <<~PENDING_COP_WARNING }
-          The following cops were added to RuboCop, but are not configured. Please set Enabled to either `true` or `false` in your `.rubocop.yml` file:
+          The following cops were added to RuboCop, but are not configured. Please set Enabled to either `true` or `false` in your `.rubocop.yml` file.
         PENDING_COP_WARNING
 
         let(:inspected_output) { <<~INSPECTED_OUTPUT }
@@ -327,9 +327,9 @@ class SomeCop < Cop
 
               remaining_range =
                 pending_cop_warning.length..-(inspected_output.length + 1)
-              pending_cops = output[remaining_range].split("\n")
+              pending_cops = output[remaining_range]
 
-              expect(pending_cops).to include(' - Style/SomeCop (0.80)')
+              expect(pending_cops).to include("Style/SomeCop: # (new in 0.80)\n  Enabled: true")
 
               manual_url = output[remaining_range].split("\n").last
 
@@ -346,9 +346,9 @@ class SomeCop < Cop
 
               remaining_range =
                 pending_cop_warning.length..-(inspected_output.length + 1)
-              pending_cops = output[remaining_range].split("\n")
+              pending_cops = output[remaining_range]
 
-              expect(pending_cops).to include(' - Style/SomeCop (N/A)')
+              expect(pending_cops).to include("Style/SomeCop: # (new in N/A)\n  Enabled: true")
 
               manual_url = output[remaining_range].split("\n").last