Update macOS.gitignore

[jefferyto]

Reasons for making this change

This is a continuation of #2901, to add missing metadata and system files.

Changes I made:

• Fixed/updated links
• Omitted the HFS+ hardlink directories commit (https://github.com/github/gitignore/pull/2901/commits/0b29bbec71f5fde17f5365e2150af562c83383ec)
• Added a commit to ignore .HFS+ Private Directory Data\r (one of the rules from the omitted commit) using the same character class notation as for Icon\r

Links to documentation supporting these rule changes

Links are in each commit's description. (There are a few commits without supporting links; while there are lots of links for Stack Exchange/Apple Support Community/Reddit for these, I wasn't able to find any official documentation.)

If this is a new template

Not a new template.

Merge and Approval Steps

• [x] Confirm that you've read the contribution guidelines and ensured your PR aligns
• [ ] Ensure CI is passing
• [ ] Get a review and Approval from one of the maintainers