Docs: Update contributing pages with metadata

doc/development/contributing/community_roles.md

+---
+stage: none
+group: Development
+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/#designated-technical-writers
+---
+
 # Community members & roles
 
 GitLab community members and their privileges/responsibilities.

doc/development/contributing/design.md

+---
+type: reference, dev
+stage: none
+group: Development
+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/#designated-technical-writers
+---
+
 # Implement design & UI elements
 
 For guidance on UX implementation at GitLab, please refer to our [Design System](https://design.gitlab.com/).

doc/development/contributing/index.md

+---
+type: reference, dev
+stage: none
+group: Development
+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/#designated-technical-writers
+---
+
 # Contribute to GitLab
 
 Thank you for your interest in contributing to GitLab. This guide details how

doc/development/contributing/issue_workflow.md

+---
+type: reference, dev
+stage: none
+group: Development
+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/#designated-technical-writers
+---
+
 # Issues workflow
 
 ## Issue tracker guidelines

doc/development/contributing/merge_request_workflow.md

+---
+type: reference, dev
+stage: none
+group: Development
+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/#designated-technical-writers
+---
+
 # Merge requests workflow
 
 We welcome merge requests from everyone, with fixes and improvements

doc/development/contributing/style_guides.md

+---
+type: reference, dev
+stage: none
+group: Development
+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/#designated-technical-writers
+---
+
 # Style guides
 
 ## Editor/IDE styling standardization