When resolving documentation for code completion items, we fetch full
documentation through the newly added
`swiftide_completion_item_get_doc_full_copy` SourceKitD function, if not
found we fallback to brief documentation as before using
`swiftide_completion_item_get_doc_brief`.
> [!NOTE]
> Unlike brief documentation, SourceKitD doesn't cache full
documentation for completion results to avoid bloating memory with a lot
of large strings.
>
> As of now, SourceKit-LSP doesn't cache completion item documentation
either, should we introduce a new full documentation cache (e.g. using
`LRUCache`)?
There is only one real class that implements the `SourceKitD` protocol, so there really isn’t any need for the protocol + class split at all. Unify them to make code simpler to reason about.
I feel like the implementations are actually simpler if we split them. This will also allow us to add more advanced logic to the JSON compilation database build system in the future, such as inferring the toolchain from the compile command.
This adds a sourcekitd plugin that drives the code completion requests. It also includes a `CompletionScoring` module that’s used to rank code completion results based on their contextual match, allowing us to show more relevant code completion results at the top.
