3137: Do not register all proposed features r=matklad a=kjeremy
Instead only opt-in to CallHierarchy since it has a vscode API but LSP support
is still proposed.
Discovered while working on SemanticTokens which does not have a vscode API
and is still in the proposed state. Somehow enabling it would crash the
language server.
See https://github.com/microsoft/vscode-languageserver-node/issues/572
Co-authored-by: kjeremy <kjeremy@gmail.com>
7c1fb6caa5
