Update Pokémon models to Smithy IDL v2 (#3494)

## Motivation and Context
Resolves [issue
2523](https://github.com/smithy-lang/smithy-rs/issues/2523) to migrate
to Smithy IDL v2

## Description

I followed the [Smithy Migration
Guide](https://smithy.io/2.0/guides/model-translations/migrating-idl-1-to-2.html)
to convert the models. One change was that by moving the inputs/outputs
into the operation, it did result in a renaming of the CapturePokemon
structures. They went from CapturePokemonEvents(Input|Output) to
CapturePokemon(Input|Output). From a brief look at the commit history,
it seems the API used to be named different and the inputs/outputs
weren't renamed at that time. So I decided to have them match the normal
naming convention (it didn't seem to break any tests).

## Testing
As this was my first commit, I ran almost every target I could discover,
but I think the key ones were:
* codegen-server-test
* codegen-client-test
* examples: `make test`

## Checklist
<!--- If a checkbox below is not applicable, then please DELETE it
rather than leaving it unchecked -->
- [ ] I have updated `CHANGELOG.next.toml` if I made changes to the
smithy-rs codegen or runtime crates
- [ ] I have updated `CHANGELOG.next.toml` if I made changes to the AWS
SDK, generated SDK code, or SDK runtime crates

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