[BirdgeJS] Generated swift sources and `swift format`

[sliemeobn]

I use swift package birdge-js to pre-generate my source code in an interop target.
unfortunately, the my CI step swift format lint does not like these sources one bit...

it is surprisingly difficult to exclude a folder or a pattern from swift lint, adding
// swift-format-ignore-file
at the top of each generated swift file seems to be the easiest option.

since I image this will be a pretty common setup, we could remove some friction is we just added this by default in the codegen?