chore(CI/CD): Remove codeowners from /docs directory (#8737)

## Summary

This PR removes codeowners from the `/docs` directory, allowing any team
member with repo write permissions to review and approve PRs involving
documentation.

## Related Issues / Discussions

Documentation review is a shared responsibility.

## QA Instructions

None needed.

## Merge Plan

Simple merge.

## Checklist

- [X] _The PR has a short but descriptive title, suitable for a
changelog_
- [ ] _Tests added / updated (if applicable)_
- [ ] _❗Changes to a redux slice have a corresponding migration_
- [ ] _Documentation added / updated (if applicable)_
- [ ] _Updated `What's New` copy (if doing a release after this PR)_

Author: blessedcoolant

.github/CODEOWNERS

@@ -1,9 +1,9 @@
 # continuous integration
 /.github/workflows/  @lstein @blessedcoolant  
 
-# documentation
-/docs/ @lstein @blessedcoolant  
-/mkdocs.yml @lstein @blessedcoolant  
+# documentation - anyone with write privileges can review
+/docs/
+/mkdocs.yml
 
 # nodes
 /invokeai/app/ @blessedcoolant @lstein @dunkeroni @JPPhoto