Add group assignments to API documentation

Update previously unassigned topics.

doc/api/README.md

 ---
-stage: none
-group: unassigned
+stage: Create
+group: Ecosystem
 info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#assignments
 ---

doc/api/admin_sidekiq_queues.md

 ---
-stage: none
-group: unassigned
+stage: Enablement
+group: Distribution
 info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#assignments
 ---

doc/api/api_resources.md

 ---
-stage: none
-group: unassigned
+stage: Create
+group: Ecosystem
 info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#assignments
 ---

doc/api/applications.md

 ---
-stage: none
-group: unassigned
+stage: Manage
+group: Access
 info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#assignments
 ---

doc/api/avatar.md

 ---
-stage: none
-group: unassigned
+stage: Manage
+group: Access
 info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#assignments
 ---

doc/api/broadcast_messages.md

 ---
-stage: none
-group: unassigned
+stage: Growth
+group: Activation
 info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#assignments
 ---

doc/api/custom_attributes.md

 ---
-stage: none
-group: unassigned
+stage: Create
+group: Ecosystem
 info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#assignments
 ---

doc/api/dependencies.md

 ---
-stage: none
-group: unassigned
+stage: Secure
+group: Composition Analysis
 info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#assignments
 ---

doc/api/events.md

 ---
-stage: none
-group: unassigned
+stage: Manage
+group: Compliance
 info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#assignments
 ---
-# Events
+# Events API
 ## Filter parameters

doc/api/graphql/audit_report.md

 ---
-stage: none
-group: unassigned
+stage: Create
+group: Ecosystem
 info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#assignments
 ---

doc/api/graphql/getting_started.md

 ---
-stage: none
-group: unassigned
+stage: Create
+group: Ecosystem
 info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#assignments
 ---

doc/api/graphql/index.md

 ---
-stage: none
-group: unassigned
+stage: Create
+group: Ecosystem
 info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#assignments
 ---

doc/api/graphql/sample_issue_boards.md

 ---
-stage: none
-group: unassigned
+stage: Plan
+group: Project Management
 info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#assignments
 ---

doc/api/graphql/users_example.md

 ---
-stage: none
-group: unassigned
+stage: Create
+group: Ecosystem
 info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#assignments
 ---

doc/api/group_badges.md

 ---
-stage: none
-group: unassigned
+stage: Manage
+group: Access
 info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#assignments
 ---

doc/api/group_level_variables.md

 ---
-stage: none
-group: unassigned
+stage: Verify
+group: Continuous Integration
 info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#assignments
 ---

doc/api/import.md

 ---
-stage: none
-group: unassigned
+stage: Manage
+group: Import
 info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#assignments
 ---

doc/api/issue_links.md

 ---
-stage: none
-group: unassigned
+stage: Plan
+group: Project Management
 info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#assignments
 ---
@@ -30,7 +30,7 @@ Parameters:
   {
     "id" : 84,
     "iid" : 14,
-    "issue_link_id": 1
+    "issue_link_id": 1,
     "project_id" : 4,
     "created_at" : "2016-01-07T12:44:33.959Z",
     "title" : "Issues with auth",

doc/api/issues_statistics.md

 ---
-stage: none
-group: unassigned
+stage: Plan
+group: Project Management
 info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#assignments
 ---

doc/api/license.md

 ---
-stage: none
-group: unassigned
+stage: Growth
+group: Activation
 info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#assignments
 ---