TrailingCommas rule

[d-aleksandrov]

Mark last function parameter as warning if comma is losed
Bad

class Params(
    val one: Int,
    val two: Int
)

class Params(val one: Int, val two: Int)

Good

class Params(
    val one: Int,
    val two: Int,
)

class Params(val one: Int, val two: Int)

Kotlin Convention page
https://kotlinlang.org/docs/coding-conventions.html#trailing-commas

[cortinico]

Closing as this is a duplicate of #2398

We believe this is a better fit for ktlint: pinterest/ktlint#709
If there is no progress on KtLint side we might consider offering a first party rule (feel free to propose a PR or Draft) 👍

[cortinico]

Just a small heads up that it seems like this is coming to KtLint, hence will be available through detekt-formatting soon: pinterest/ktlint#709 (comment)