Add trailing commas to all generated Kotlin declarations

[PVGH19]

Generated Kotlin now emits a trailing comma on the last element of every multi-line, comma-separated construct.

What changed

Trailing comma added to the last element of:

• sealed-class constructors (AnalyticsEvent, AnalyticsProperty)
• generated data class parameter lists
• mapOf(...) and arrayOf(...) entries
• enum entries (events, properties, destinations, special enums)

Touches the 6 Kotlin templates and the kotlin_generator spec fixtures.
Swift output is unchanged.

Effect on consumers

Regenerating in an Android project produces only trailing-comma diffs on the generated files (verified against real sheet data).

Testing

bundle exec rspec — 67 examples, 0 failures.