Default `show_inherited_labels` to true

Projects and subgroups can use all inherited labels but their
labels pages do not show all inherited labels. This commit
defaults `show_inherited_labels` to true to turn on this
feature to make available labels more visible.

app/controllers/concerns/show_inherited_labels_checker.rb

@@ -6,6 +6,6 @@ module ShowInheritedLabelsChecker
   private
 
   def show_inherited_labels?(include_ancestor_groups)
-    Feature.enabled?(:show_inherited_labels, @project || @group) || include_ancestor_groups # rubocop:disable Gitlab/ModuleWithInstanceVariables
+    Feature.enabled?(:show_inherited_labels, @project || @group, default_enabled: true) || include_ancestor_groups # rubocop:disable Gitlab/ModuleWithInstanceVariables
   end
 end

changelogs/unreleased/241990-default-show_inherited_labels-feature-flag-to-true.yml

+---
+title: Show all inherited labels in projects and subgroups
+merge_request: 45161
+author:
+type: added

config/feature_flags/development/show_inherited_labels.yml

 ---
 name: show_inherited_labels
 introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/42960
-rollout_issue_url:
+rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/267547
 group: group::project management
 type: development
-default_enabled: false
+default_enabled: true

doc/user/project/labels.md

@@ -57,9 +57,11 @@ and edit labels.
 
 ### Project labels
 
+> Showing all inherited labels [introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/241990) in 13.5.
+
 To view the project labels list, navigate to the project and click **Issues > Labels**.
 The list includes all labels that are defined at the project level, as well as all
-labels inherited from the immediate parent group.
+labels defined by its ancestor groups.
 For each label, you can see the project or group path from where it was created.
 You can filter the list by entering a search query at the top and clicking search (**{search}**).