Add non-manifest CoPilot instructions #323704
Description
Description of the new feature/enhancement
Similar to #320873, create an instructions file targeting the non-manifest portions of the repository (while maintaining that the bot should stay out of the manifests directory).
Proposed technical implementation details (optional)
Create a copy of the current manifest instructions and update for non-manifest purposes. Target everything but the manifests. Unfortunately, the glob syntax samples contain no negation, but existing negation syntax should be attempted (https://docs.github.com/en/actions/reference/workflows-and-actions/workflow-syntax#filter-pattern-cheat-sheet).