Composed extensible record types should support multiline formatting

I use the extensible record syntax to compose larger records types. Why I do this is a long story, but mostly it is related to modularity.

## Example
Example of composing two records:
```elm
type alias Part1 a =
{ a
| part1 : Int
}

type alias Part2 a =
{ a
| part2 : String
}

-- The composed record looks like this

type alias Composed =
Part1 ( Part2 {} )

```

Now, when composing many parts I like to split the declaration on multiple lines:

This would be one way to do this:
```elm
type alias Composed =
Part1
( Part2
( Part3
( Part4 {}
)
)
)

```

However, with 20 parts it becomes very difficult to read so I usually do more of a "lisp" style. Maybe not very elegant, but it works. It is easy to read and modify.

Something like this:
```elm
type alias Composed =
Part1
( Part2
( Part3
( Part4 {}
)))
```
Sometimes the parts also have parameters:
```elm
type alias Composed =
Part1
( Part2 Int Msg
( Part3 Msg
( Part4 {}
)))
```
## Problem

`elm-format` implodes the above to one line, which makes it really difficult to maintain or read.

I don't know which coding style is correct, but I certainly prefer the "lisp" style when there are many parts.

Any thoughts on this? Is this something that should be fixed in elm-format?

The issue names no source file or test. Begin by reproducing the multiline extensible-record examples with elm-format, then trace the formatter entry point handling these type-alias declarations; done requires an agreed multiline formatting rule and coverage for the reported examples.

Written by the indexing model from the issue text.