Questions:
- `getDocumentSymbolsInternal`: from looking at the code + cross referencing VSCode Api, looks like its just used to enumerate document symbols
(call tree: `documentSymbol()->getDocumentSymbols()->getDocumentSymbolsInternal()`)
- sanity check: are there any other places this modification needs to be propogated?
- sanity check: specifically so that symbol resolve/rename/goto def/etc aren't broken?
- error handling: unsure what the pre/post conditions are of the parse tree when `getDocumentSymbolsInternal` is invoked
so there might be superflous guards/checks
- any tests to add?