We have diagnostics in place that point out unnecessary things:

• Unnecessary @Autowired annotation on constructors
• Unnecessary @PathVariable annotation when the name matches the parameter name
  (maybe more?)

We should include the DiagnosticTag.Unnecessary in the resulting diagnostic marker. It allows the client to render the part in the editor faded out.

https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#diagnosticTag

(Whether this works in Eclipse would be an additional thing to verify)