[Feature Request] ---@final to mark class method as non-overridable

In languages like Java, you have the keyword final to indicate that a function should NOT be overridden. There doesn't seem to be any annotation like that yet. It should give a warning (or error?) if you try to override the function. Additionally, completion for function MyClass: could avoid suggesting anything with @final? You'd still be able to call it anywhere, just not override it if its now final.

(Maybe @final could also work on variables? Pretty much working the same way, just "don't override/set this but still be able to read it")

(Unrelated but I was thinking about ---@override to mark something as "you should override this and not call this" but it wouldn't be able to warn since your internal code needs to call it, so I'm not sure. Might just be good to have anyway, not as a warning but a tooltip thing.)

No source file, test, or entry point is named. First clarify whether @final applies to methods, variables, or both, and whether violations produce warnings or errors; then inspect the language server's annotation, override-checking, and completion behavior. Done means the chosen semantics are implemented consistently and covered by diagnostics or completion tests.