`textDocumentContent` capability/feature is still behind a proposed gate even though in 3.18 it's not flagged as proposed anymore

[DavyLandman]

Looking at src/common/client.ts the TextDocumentContentFeature is still only inside the ProposedFeatures namespace. But if I understand the specification correctly, it's not a proposed part anymore, it's now finalized?

What are the steps to make this a supported capability in VS Code (I'm willing to open a PR)? Or is it still not released to VS Code for a different reason?

Alternatively: what flag for VS Code is needed to enable this proposed LSP api? As it does not correspond to a proposed API in VS Code.

[DavyLandman]

Ah, I need to use LanguageClient::registerProposedFeatures()

[dbaeumer]

Good catch. Will fix this.