0619c67ac6
If `hierarchicalDocumentSymbolSupport` is not true in the client capabilites then it does not support the `DocumentSymbol[]` return type from the `textDocument/documentSymbol` request and we must fall back to `SymbolInformation[]`. This is one of the few requests that use the client capabilities to differentiate between return types and could cause problems for clients. See https://github.com/microsoft/language-server-protocol/pull/538#issuecomment-442510767 for more context. Found while looking at #144