Improve parser error message for elm-style records

[rtfeldman]

{ x = 5 } causes a panic

[ayazhafiz]

No longer a panic but error message could be better

» { x = 5 }

── RECORD PARSE PROBLEM ────────────────────────────────────────────────────────

I am partway through parsing an record, but I got stuck here:

1│  app "app" provides [replOutput] to "./platform"
2│
3│  replOutput =
4│      { x = 5 }
        ^

TODO provide more context.

[isaacvando]

Still relevant