SetField does nothing

[MattiaVerticchio]

Hi! First and foremost, thank you for creating elm-pages! 😁

I'm working on a hobby project and implementing a simple suggestion box with autocomplete functionality using the Forms API. My goal is to have a click on a suggestion automatically populate the input field. I tried using the built-in Effect.SetField, but it didn't produce any results.

Upon examining the source code in src/Pages/Internal/Platform.elm, I discovered that this feature hasn't been implemented yet. I'm curious about how this should work. If it's simply a matter of using Dict.insert to add the new value to model.pageFormState, I'd be happy to submit a pull request if you're open to that.

Please let me know your thoughts on this approach or if you have any alternative plans, thank you again!