Completes the TODO in GHOST_SystemPathsCocoa::addToSystemRecentFiles
Also renames the filename parameter to the more appropriate filepath.
The recently opened/saved file will now also show up in:
- Blender Dock icon > Right click.
- Three finger swipe down in Open Blender i.e., App Expose
Based on a earlier contribution by @jenkm.
Pull Request: https://projects.blender.org/blender/blender/pulls/107174