update cocoa crate

[michaelkirk]

• Tested on all platforms changed
• Compilation warnings were addressed
  • Left pre-existing deprecation warnings for err.description
• cargo fmt has been run on this branch
• cargo doc builds successfully
• [n/a] Added an entry to CHANGELOG.md if knowledge of this change could be valuable to users
• [n/a] Updated documentation to reflect any user-facing changes, including notes of platform-specific behavior
• [n/a] Created or updated an example program if it would help users understand this functionality