Feature Request: Support trailing comma for function arguments.

[markwongsk]

Support trailing comma rule/enhance trailing comma rule for function args.

As per microsoft/TypeScript#7279, functions now support trailing commas for their arguments.

[adidahiya]

nice, thanks for the heads up! I'm looking forward to this

[markwongsk]

How far do we want to take this trailing comma rule? For example, type parameters and function types can also be linted:

var a: (
    foo: string,
    bar: string,
) => string

and

function foo<
    T,
    U,
    V,
>(firstArg: string, secondArg: string) { return 42; }

[adidahiya]

I'd say +1 for all of those @markwongsk -- anywhere a trailing comma is supported and a list is multiline, we should lint it

[timocov]

@adidahiya What do you think about be able to disable it for multiline (maybe for singleline too)?