LSP Semantic Token Decoder, Improve LSP-CodeFileDoc Arch

[thecoolwinter]

Description

• Implements a decoding object for LSPs to translate the compressed LSP semantic token objects to a format CodeEditSourceEditor can read. See spec.
• Improves the relationship between language servers and code files architecturally.
  • Moves ownership of lsp content coordinators to language server object. This improves the readability of the content coordinator as it now has a non-optional initializer.
  • Adds didOpen/didClose notifications to CodeFileDocument, allowing it to tell anyone who needs to know (LSP, future extensions) that it was opened. This helps decouple the document object from LSP, though there is still a reference to the LSP through the published lspCoordinator property.
  • Updates the LanguageServerFileMap class to be more extendable as more objects are added for coordinating LSP-document interactions.

This architectural change could be improved further. However I think making this change larger is worse overall. In the future I'd like to make a protocol that the language server can consume for documents, that CodeFileDocument conforms to via an extension. That should make things easier to test too.

One small change that went with the second point

• Moved dep injection initialization to the SwiftUI app initializer as it happens before anything in AppDelegate.

Related Issues

• ✨ Semantic Highlights #1950

Checklist

• I read and understood the contributing guide as well as the code of conduct
• The issues this PR addresses are related to each other
• My changes generate no new warnings
• My code builds and runs on my machine
• My changes are all related to the related issue above
• I documented my code

Screenshots

N/A

[austincondiff]

Looks good from what I can tell!