Fix RuboCop command in linters documentation

- Change 'rubocop -a' to 'bundle exec rubocop -A'
- Use bundle exec as per CLAUDE.md requirements
- Use -A flag instead of deprecated -a flag

Co-authored-by: Justin Gordon <[email protected]>

Author: github-actions[bot]

docs/contributor-info/linters.md

@@ -10,7 +10,7 @@ If you haven't tried the autofix options for `eslint` and `rubocop`, you're seri
 2. **Rubocop:** Be sure to be in the correct directory where you have Ruby files, usually the top level of your Rails project.
 
 ```bash
-rubocop -a
+bundle exec rubocop -A
 ```
 
 3. **ESLint:** Be sure to be in the correct directory where you have JS files.