`.sourcekit-lsp/config.json` doesn't allow passing traits
Description
The configuration file allows selecting Swift SDK and triple, but selecting package traits for indexing is currently not possible.
https://github.com/swiftlang/sourcekit-lsp/blob/d5978d5f8c6c32ab50f8265a53caff3defe4952e/Documentation/Configuration%20File.md?plain=1#L17
Synced to Apple’s issue tracker as rdar://144557689
This probably needs to go hand in hand with vscode-swift support to select the enabled traits for the root package.
I don't think VS Code support should preclude any improvements in this area. There are other editors that would benefit from it either way, and VS Code users are free to edit the config file directly in the meantime.
This should have been fixed by https://github.com/swiftlang/sourcekit-lsp/pull/1973.