Migrate examples to Swift snippets

[fwcd]

This recently merged proposal will bring native support for running small scripts (snippets) in the context of the package directly via SPM (swift run [snippet]). Since the examples from this repo effectively serve the same purpose, this branch renames the Examples folder to Snippets to make them discoverable by SPM. Additionally, it adds a few minor tweaks (cleaning up the paths in the README.md and using trailing closures in the syntax builder example).

[kimdv]

Cool! 🎉

[fwcd]

I have rebased and tested this with a recent toolchain, swift build now builds the snippets too. The only thing left to do would be to update the build script, so the snippets are built/checked in CI too. Is there a way to do so without having to explicitly list all snippets in build_command?

[ahoppen]

My idea would be to change Builder.build() to build all products (i.e. remove the --product option from the swift build invocation). That could give us a performance improvement because all products are built in parallel and also builds the snippets.

[fwcd]

Since this PR doesn't really regress anything regarding the snippets/examples, wdyt about moving the updates to the build script to a future PR once we figure out #531?

@swift-ci please test

[ahoppen]

Sounds good to me 👍

[fwcd]

The CI failure looks unrelated, if I read this correctly? I could try again later.

[ahoppen]

I think CI got confused because you mentioned another PR in the same comment that you triggered CI, so it tried to test this PR together with the mentioned PR.

[ahoppen]

@swift-ci Please test