cross-compile codegen module against scala3

[ghostbuster91]

PR Checklist (not all items are relevant to all PRs)

• Added unit-tests (for runtime code)
• Added bootstrapped code + smoke tests (when the rendering logic is modified)
• Added build-plugins integration tests (when reflection loading is required at codegen-time)
• Added alloy compliance tests (when simpleRestJson protocol behaviour is expanded/updated)
• Updated dynamic module to match generated-code behaviour
• Added documentation
• Updated changelog

[kubukoz]

homestly I think we should just use scalameta for small things like these (rendering constants)

[Baccata]

fine, if you want to pull it I don't mind. But don't get your hopes up about rewriting the codegen in scalameta

[kubukoz]

yeah I'm not

[ghostbuster91]

I tried it in the past and while having the snippets to compile at the same time you compile your code is mind-blowing there was a lot of hassle sometimes to get them right.

[Baccata]

yeah, the ancestor to smithy4s was actually written with scalameta. Lots of friction.

[kubukoz]

hints:

• libraryDependencies += ("org.scalameta" %% "scalameta" % "4.11.0").cross(CrossVersion.for3Use2_13)
• scala.meta.Lit.String(s).printSyntaxFor(scala.meta.dialects.Scala3)

that's how I use it in https://github.com/kubukoz/smithy-playground/blob/c34be16f534795041295f4379a6ca8040297c4b1/modules/parser-gen/src/main/scala/playground/parsergen/ParserGen.scala#L355C25-L355C92 anyway

[kubukoz]

we'll need this for #1790. @ghostbuster91 how do you feel about finishing this up?

[ghostbuster91]

Sounds like a good case. I will try to do this this week.