I was under the impression that rust-analyzer (and more generally LSP) provides augmentative (contextual) syntax highlighting, whereas most of the highlighting still comes from editor-specific configuration. Is this not the case? If so I would be thrilled; as someone authoring a custom language right now it has been very frustrating to not be able to provide a single source of syntax highlighting for all popular editors.
rust-analyzer highlights everything, I have an empty vs code theme for it somewhere. But yeah, in general LSP highlighting is specified in augmentative way.