feat: generate operation samples

Issue \

Implements support for generating samples from the examples trait.
Cleans up ShapeValueGenerator a bit to make the output formatting nicer (we previously only used it for generating protocol tests so minor formatting issues weren't a big deal but they should be cleaner for docs).

Code is output to src/samples directory. Samples are not automatically included by dokka, you have to update the configuration to get them included.
We decided to omit doing anything with the output of the examples trait and to omit error examples. It isn't clear what customer benefit there is to including them and instead decided to focus samples on making a request for the given operation.
This renders using the playground by default which won't actually work, see https://github.com/Kotlin/dokka/issues/3041. We will likely hold off merging this until that is disabled.

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