Add new playground types

[award999]

Needed to get playground support into SourceKit-LSP: swiftlang/sourcekit-lsp#2340

[owenv]

I think this needs to capture either the corresponding product or target as well so that the playground can be executed in the appropriate context

[award999]

@owenv the LSP code that parses these does include the target https://github.com/swiftlang/sourcekit-lsp/pull/2340/files#diff-d76b1dc09dd52af2a88684043d44d1e5261f013c09f6137dffd4e23aebce6e56R91 but do you want the comment code to reflect the expected format?

[award999]

I added a better explanation about id but let me know if there is more you wanted

[owenv]

Hmm, so it seems like the playgrounds implementation is building a dylib composed of every target in the package and linking the runner against that. This will work in small examples, but in general it's not safe to assume all the targets in a package can be safely linked into a single image. e.g. they may have different platform requirements, conflicting static initializers, multiple copies of a binary dependency built from the same sources, etc. I think sourcekit-lsp will need to pick a single specific appropriate library product containing the playground's code, thread that through to the play command, and adjust the build of the runner accordingly

[award999]

Whatever swift play --list returns is what I think we should aim to match, and then VSCode executing swift play myPlaygroundID should make sure the right one is built and run

[award999]

Any further comments @owenv? Can we merge and tag a new release?

[ahoppen]

A couple small comments, otherwise LGTM.