Add Swift 5.8 Support

[jpsim]

• Add type hints to resolve Swift 5.8 warnings
• Add 5.8 test fixtures
• Adjust compiler versions in tests
• Add source.lang.swift.syntaxtype.operator syntax kind
• Add source.lang.swift.decl.macro declaration kind
• Add new declaration attribute kinds

[jpsim]

I'll add Swift 5.8 CI jobs in a follow-up PR.